SAT math, sat math part 2, omg
The exponential graph increases below the X axis (from left to right) when _____ OR ______
"a" is NEGATIVE, b≥1, "c" is NEGATIVE OR "a" is NEGATIVE, 0<b<1, "c" is POSITIVE
The exponential graph decreases below the X axis (from left to right) when _____ OR ______
"a" is NEGATIVE, b≥1, "c" is POSITIVE OR "a" is NEGATIVE, 0<b<1, "c" is NEGATIVE
The exponential graph decreases above the X axis (from left to right) when _____ OR ______
"a" is POSITIVE, b≥1, "c" is NEGATIVE OR "a" is POSITIVE, 0<b<1, "c" is POSITIVE
The exponential graph increases above the X axis (from left to right) when _____ OR ______
"a" is POSITIVE, b≥1, "c" is POSITIVE OR "a" is POSITIVE, 0<b<1, "c" is NEGATIVE
How to solve: What is P percent of T?
(P/100) (t)
How to solve: S is P percent of what total amount?
(S/total) = P percent convert P percent to decimal
a² - b²
(a - b)(a + b)
Area of a sector (central θ in degrees) =
(central angle) / (360°) * (π * r²)
Area of a sector (when θ is in radians)
(central θ in radians / 2) * r²
x²-y²
(x + y) (x - y)
All points INSIDE of a CIRCLE follow the inequality
(x-h)² + (y-k)² < r²
general form of a circle
(x-h)² + (y-k)² = r²
All points OUTSIDE of a CIRCLE follow the inequality
(x-h)² + (y-k)² > r²
Absolute value graph parent function
- shaped like a V - f(x) = |x|
slope of a line in a Standard form linear equation
-(A) / B
For quadratic equations, the formula for sum of the solutions is
-(b)/a
The roots of the product (AC) method are
-(r)/a & -(s)/a
How to find the x-value of the vertex
-b /2a
If Solution A is 20% glucose by mass and we have "A" kilograms, then amount of glucose in Solution A is
0.2A
If Solution B is 30% glucose by mass and we have "B" kilograms, then amount of glucose in Solution B is
0.3B
When a value is increased by a percentage, you need to multiply the value by
1 PLUS the decimal form of the percent increase
{1, 2, 3, 2, x}, Mean = 4. Solve for x
1+2+3+2 =8 8+x / 5 values = 4 8 + x = 5*4 x =12
How to find the center given the 2 endpoints of a diameter,
1. (x1 + x2)/2 = X value of the center 2. (y1 + y2)/2 = Y value of the center
Paula bought a dress at a store that gave her a 30 percent discount off the original price. The total amount she paid to the cashier was "p" dollars, including a 9 percent sales tax on the discounted price. What represent in the original price of the dress in terms of p?
1. 0.7X 2. 9/100 +1 =1.09 3.You multiply with percentage so (0.7x)(1.09) 4. 1.09(0.7)(x) = P 5. Divide 1.09 and 0.7 6. p/ (1.09)(0.7) = X
If 6 guests are assigned to each table, 3 additional tables will be needed. If 12 guests are assigned to each table, 3 tables will not be used. How many guests are there?
1. 6 guests * 3 tables = 18 guests 12 guests * 3 = 36 guests. 2. 6(tables) + 18 = guests 12(tables) - 36 = guests 3. 6T + 18 = 12T -36 T = 72
product (AC) method
1. Find 2 numbers, r & s, that add up to (B) and equal (A*C) when multiplied r+s = B r * s = A*C
Kenny enlarged the area of the photograph to 150% of its original size. The original dimensions of the photograph were 3 inches by 5 inches. What is the area of the new enlarged photograph.
1. Find the area of the original dimension 3 x 5 =15 2. Realize the problem says enlarged TO 150% not BY so Area(1.5) equals the original dimension 3. 15(1.5) = 22.5
When given a set of data box plot and asked to find Q1 & Q3, you must
1. First find the position of the median 2. Divide that position by 2. (lets call the answer Y) 3. Add Y to the position of the median. This answer is the position of the value that makes Q3 4. Subtract Y from the position of the median. This answer is the position of the value that makes Q1
485] Greasy Stank slop has a serving size of 7/8 cup and provides 280 calories. Chris mixes Greasy Stank slop with Unctuous Stank slop for his breakfast. Unctuous Stank slop provides 300 calories per cup. If the total number of calories in one cup of Chris's mixture is 315, how much Unctuous Stank slop is one cup of the mixture.
1. Mark the Greasy Stank slop as "A", Unctuous Stank slop as "B" and the new mixture as C 2. Set up a proportion to figure out how many calories are in one cup of Greasy Stank slop. 7/8 = 280/ x 3. A + B = C 4. The question states that the mixture uses 1 cup, so C = 1 (A+B = 1) 5. Set up the other equation 320A + 300B = 315 6. Realize that A + B = 1, meaning that x + (1-x) = 1 7. 320(1-B) + 300B = 315 8. solve for B
Completing the square for Circle Equations
1. Move the constant term to the opposite side of the variable 2. Divide both sides of the equations by the coefficients of x² & y². (the coefficients must be 1) 3. Complete the square for the X terms & Y terms x² + bx --> (x + b/2)² y² + qy --> (y + q/2)² 4. Add (b/2)² & (q/2)² to the side with the constant
Victor gets paid 30% of the total retail value of the cars he sells, but he can also earn a bonus. When he earns a bonus, he is paid an additional 5% of his normal pay. During one pay period, Victor sold $8400 in used cars and earned a bonus. How much was he paid, in dollars, for this pay period?
1. Multiply 0.3(8400) 2. Multiply that value by 1.05
In a company, 15% are executives, 40% are programmers, 15% are graphic designers and the remaining 12 people are marketing representatives. How many more programmers are in the company than executives?
1. Notice that the percentages do not fully add to 100%, 15% + 15% + 40% = 70% 2. This means that the remaining 12 people represent 30% of the company 3. Set a proportion. 30/100 = 12/X X =40 4. Programmers are 40% / 0.4(40) = 16 5. Executives are 15% / 0.15(40) = 6 6. 16 - 6 = 10 Answer is 10 more people
The table shows the distribution of the number of sports that high school students play. If the number of students who participate in one sport(45%) is 80 more than the number of students who participate in two sports (20%), what is the total number of students at the school?
1. Realize that 0.45 * (the total) equals the number of students at the school 0.2 * (the total) + 80 equals the 0.45(T) 2. Set the equation to 0.2T + 80 = 0.45T and solve
The angles are acute and cos(a°) = sin(b°). If a = 5k + 15 and b = 4k -24, what is the value of k?
1. Realize that cos A = sin(90-A) or sin B=cos(90-B) 2. So either plug cos(5k+15) =sin(90-(4k-24) and solve for K OR 3. sin(4k-24) = cos(90-(5k+15) and solve for K
f(x) = 3x² + 5 and f(x+a) = 3x² - 24x + 53. What is the value of "a"?
1. Realize that if you add "a" to the original f(x) equation, the equation becomes f(x+a) 2. Plug (x+a) into the f(x) equation 3. Set the equations equal to each other 4. Match the equations
An escape room gives ratings from 0 to 100. In the first 8 ratings the escaperoom received, the average was 82. What is the least value the escaperoom can receive for the 9th rating and still be able to have an average of at least 90 for the first 15 ratings.
1. Realize that there are three parts to this problem. (The 8 ratings, 9th ratings, 10-15 ratings) 2. 90 * 15 values = 1350 ( the sum of all the values 3. 8 ratings*82 = 656 (sum of the first 8 values) 4. Realize to find the least value of the 9th rating, we need to maximize the value of the other 10-15 ratings. The average of 10-15 ratings (6 numbers) equals 100 5. 6 values * 100 = 600 6. 656 + 9th rating + 600 ≥ 1350 7. 656+600 = 1256 8. 1256 + 9th rating ≥ 1350 9. {1350-1256 = 94} 9th rating ≥ 94 Answer is 94
The function f(x) = x³ and the function g(x) = x³ - 2. Which of the following translations of the graph of "F" in xy plane causes the graph of "G"
1. Realize that there isn't any parentheses in the equation meaning that point has x=0 2. The y value equals = -2 3. This means that the value goes 2 units downward
Ex: (x-4)² + 2(x-4) -15 = 0
1. Replace (x-4) with the letter U 2. Write x - 4 = U 3. Solve for U 4. After solving for U, plug the answers into x - 4 5. Solve for X. This is your answer
In the equation, B(p) = 500(1.45)ᵖ, what is the growth B(h) that gives the number of bacteria as a function of hours,h, instead of as a function of 18 minute periods, p?
1. Set a proportion between P and H 2. Realize that the value that we are trying find equals 1 in the proportion so we're trying to find "h" so H = 1 3. P/H = /1 4. Ask how many times does 18 min fit in "H" 1 hr or 60 mins 60/18 5. Set the proportion P/H = 60/18 / 1 6. Solve for P (because we are replacing P in the original equation)
The equation, -12x²+28x-44 / ax -4 = -6x+2 - (36/ax-4), is true for all values of x≠4/a, where "a" is a constant. What is the value of "a"?
1. The quotient of this division equation is -6x+2. This means that -12x²/ax = -6x Basically, what number divided by -12 equals -6?
Franklin created a scale model of a bus where 1 inch on the model equals 4 feet on the bus. The length of the model is 9.3 inches. He makes a new model where 1 inch on the model equals 2 feet on the bus. How will the length of the new model compare to the old model?
1. The ratio of model to real bus is 1:4. 1/4 = 9.3/x x = 37.2. The length of the real model is 37.2 The new model's ratio to real bus is 1:2. 1/2 = x/ 37.2 x = 75 So the new model is 2 times the length of the first
How to figure out what the area will equal when both the length and width doubles OR when the length triples and the width doubles?
1. Write the formula for area. A = L*W 2. Follow the instruction of the question, let's say the length triples and the width doubles: Write: Area = 3L * 2W So Area is 6 times the L*W
How to figure out what the volume will equal when the length, width & height double OR when the length triples, the width doubles & height quadruples?
1. Write the formula for volume. V = L*W*H 2. Follow the instruction of the question, let's say the length triples, the width doubles & height quadruples: Write: Volume = 3L * 2W *4H So Volume is 24 times the L*W*H
A baseball coach uses the formula, K = ½mv², to find the kinetic energy of a ball moving with velocity, V, and the same ball moving with the velocity 2.5V. What is the ratio of the kinetic energy of the faster ball to the kinetic energy of the slower ball?
1. Write the ratio for K of fast ball to K of slow ball--> Kf/Ks 2. write the kinetic energy formula for Kf and Ks. 3. Replace the v in the Kf formula as 2.5v and in the Ks formula as V 4. Kf/Ks = ½m(2.5v)² / ½m(v)² 5. Cancel out ½m on the numerator & denominator 6. Because the question asks for ratio, convert 2.5 into a fraction--> 5/2 7. Distribute the ² in (5/2v)²/(v)² 8. It becomes (25/4 v²) / v² 9. Cancel out the v² 10. The answer is 25/4
What is the y intercept of the graph when y=2ˣ?
1. Y int means the value when X=0 2. Plug 0 into 2ˣ 3. 2⁰ = 1 4. The y int is (0,1)
To determine the median with a data set that has an even number of values (100 values in a dataset),
1. divide the number of values in the dataset by 2 2. The answer you get is the 1st position 3. Add 1 to the 1st position to get the second position 4. The median is between the 1st & 2nd position 5. After finding the values that make up those positions, add and divide them by 2 to get the MEDIAN
complete the square to get X
1. make sure the equation is in Ax² + Bx + C = 0 2. Move C to the other side of the equation, Ax² +Bx = C 3. Convert Ax² + Bx into (x+ (b)/2)² 4. Add (b/2)² to the side where C is & Combine 5. square both sides that are, (x+ (b)/2)² = C + (b/2)^2 6. After squaring the side of (C) + (b/2)², the answer must be written as "±" 7. Solve for the roots, zeroes
To recognize perfect square expressions
1. middle terms are products of 2 2. the last term & first term can be square rooted
The expression [ 5x + 23/ (x+4)² - 5/ (x+4) ] is equal to a /(x+4)², where a is a positive constant and x ≠ 4. What is the value of a?
1. set the expression equal to "a" /(x+4)² 2. multiply both sides by (x+4)² 3. Cancel the denominators of 5x + 23/ (x+4)² & "a" /(x+4)² 4. The (x+4)² cancels out the denom. in 5/ (x+4) but leaves 5(x+4) left. 5. Distribute and combine like terms to get "a"
2 < -3x + 2 < 8
1. subtract 2 from both sides 0 < -3x < 6 2. Divide by -3 0 > x >-2
No solution in a system of equations means
1. the lines are parallel 2. the lines do not intersect 3. the lines have same slope, different y intercepts
Infinitely many solutions in a system of equations means
1. the lines are the same line 2. the lines have the same slope and same y intercept
Using the formula [weight = 13/2 (height) + 15], and we wanted to see how much taller the object would grow to increase the weight by 1 lb,
1. we should set a proportion using the slope 13/2 2. Realize that 13/2 means (change in weight / change in height) 3. Match the values with the slope. 13/2 = 1/X 4. Solve for X
Solutions to a system (synonyms)
1. zeros 2. x coordinates of the points of intersection 3. "values that satisfy" 4. roots
With mixture problems, you need to set up 2 equations. What are they?
1st equation talks about the total amount of ONE THING 2nd equation talks about total amount of the mixture (the percentages)
A central angle of 2 radians intercepts an arc that measures
2 radiuses
Surface area =
2(height*length) + 2(length * width) + 2(width * height)
Pythag triple
20-21-29
Pythag triple
5-12-13
surface of a cube
6 * length²
Pythag triple
7-24-25
Pythag triple
8-15-17
aᵇ * aᶜ
= a ᵇ⁺ᶜ
X⁰
=1
sum of interior angles
=180(number of sides - 2)
The factored form of the product (AC) method
A(x + (r)/a) (x+ (s)/a)
kx - y =3 y = x² - k In the system of equations above, "k" is a constant. When the equations are graphed in the xy-plane, the graphs intersect at exactly two points. Which of the following CANNOT be the value of "k"?
A) 2 B) 3 C) 4 D) 5 1. Move the y in the first equation 2. Set both equations equal to each other kx - 3 = x² - k 3. Move kx -3 to the other side of the equation. x² -kx -k +3 = 0 4. Realize the equation is in Ax² +Bx +C = 0 a = 1 b=-k c= -k+3 5. The problem states that the graph has an intersection at TWO POINTS meaning that there are TWO REAL ZEROS The equation is b² - 4ac >0 6. (-k)² - 4(1)(-k+3) = k² +4k -12 7. k² +4k -12 > 0 8. Factor out k² +4k -12 --> (k+6) (k-2) 9. (k+6) (k-2) > 0 10. k = -6 & k= 2 > 0 11. K has to be greater than -6 & 2 12. The answer is A.
The line of best fit passes through the point (15, -0.31). Which of the following can be concluded?
A) A hardware store cannot have more than 14 competitors B) A hardware store with 14 competitors cannot decrease in price any further C) A hardware store with 14 competitors can no longer sell screwdrivers D) The line of best fit will not model the price well for a store with a large number of competitors.
Which option yields exponential decay of the money and why?
A) Each successive year, 5% of the initial account balance is withdrawn from the account B) Each successive year, 2% of the initial account balance and $500 is withdrawn from the account C) Each successive year, 3% of the current value is withdrawn D) Each successive year, $500 is withdrawn from the account The answer is C because 3% is taken from every CURRENT value in the account. Taking money from the initial account makes it a linear relationship
The graph of the exponential function, h, in the xy plane where y=h(x), has a y intercept of "D", where "D" is a negative constant. What is the function?
A) h(x) = d(2)ˣ B) h(x) = d(-x)² 1. The formula is y = a * bˣ 2. So "D" is in the place of "a". 3. Realize that bc the y int is "D", when X=0, y=D 4. Plug 0 where the X is
When a system of linear equation has INFINITE solutions, the ratio
A1 / B1 = A2 / B2 C1 / B1 = C2 / B2
if a model car is built at a 1:20 scale,
ANY MEASUREMENT on the model will be 1/20 of the same measurement on the real car.
Formula for mean
Average = (sum of values) / (size of data set)
distance/time/speed equation
Average speed = (total distance)/(total time)
When parallel lines are written in Standard form, the
Ax + By = Ax + By C≠C x & y coefficients match in both equations
Standard form linear equation
Ax + By = C
When a system of linear equation has NO solutions, the ratio
Ax1 + By1 =C1 Ax2 + By2 = C2 A1 / B1 = A2 / B2 C1 / B1 ≠ C2 / B2
y intercept slope of a line in a Standard form linear equation
C/B
Radians =
Degrees * (π/180)
INSCRIBED ANGLE and its measure is
HALF THE MEASURE OF THE CENTRAL ANGLE
If Solution C is made by mixing Solution A (20%) & B (30%), and it contains "K" kilograms of glucose, what is the formula?
K = 0.2A + 0.3B
When a value X is increased by 200%, you need to multiply the value by what and why?
Multiply by 3 because 1 + 2 (the decimal form of 200) equals 3.
150 is 50% more than 100 (bc of 1.5*100), but 100 is
NOT 50% LESS THAN 150
Given the statement: X is 80% of Y, you should
NOT WRITE y=1.2x
If a jacket originally priced at "J" dollars was on sale for 10% off and you paid P dollars for the jacket, what is the equation?
P = 0.9(J)
The line of best fit in a scatterplot is a ________, so we must make __________ claims about the values it gives.
PREDICTION, GENERAL
For a polynomial p(x), the value of p(6) is 4. What is true about p(x)?
The remainder of p(x) when divided by (x - 6) is 4
How to find median of frequency table?
Use the Sum of the frequencies. They will tell you the positions of the values
high standard deviation
When all the values are more spread out and away from the mean (kinda forms a box if it was a bar graph)
low standard deviation
When all the values cluster/circle/focus around the mean (kinda looks like a peak)
horizontal line equation
Y = a number
percent change formula
[(New value - original value)/ original value] * 100
With frequency tables, the mean is equal to
[value(frequency) + value(frequency) + value(frequency) / sum of all the frequencies
For polynomial long division, you must STOP when
a constant is left over and write the (constant/divisor)
when the inequality sign is > or ≥, you shade
above the line
To determine the median with a data set that has an odd number of values (99 values in a dataset),
add 1 to the size of the data set and then divide by 2 to determine the POSITION of the median Ex: 99 values in a data set + 1 = 100 100/2 = 50. The median is in the 50th position
angles formed by crossing parallel lines
all the obtuse angles are equal to each other all the acute angles are equal to each other
In the formula to calculate percent change, the denominator is
always the original value
Perpendicular lines have
an opposite reciprocal of the other line
proportion w/ arc length & circumference
arc length / circumference = x° / 360°
(a+b)²
a² + 2ab + b²
(a-b)²
a² - 2ab + b²
1/a⁻ᵇ
aᵇ
aᵇ / aᶜ
aᵇ⁻ᶜ
when the inequality sign is < or ≤, you shade
below the line
When a polynominal raised to an even power, the line
bounces off the point
For quadratic equations, the formula for product of the solutions is
c / a
In the equation, weight = 13/2 (height) + 15, what does the slope mean
change in weight /change in height. An object that weight 15 lbs will increase by 13 lbs as the height increases by 2 inches
slope can equal
change in y value / change in x value
sin (x) =
cos(90 -x)
when the inequality sign is a < or >, the line is a
dashed line
density formula
density = mass / velocity
when you are unsure about the ratios,
draw a picture
When a polynomial f(X) is divided by a binomial x - r, the remainder is
equal to f(r)/ you must plug in "r" into the polynomial to find the remainder
When a polynomial f(x) is divided by a binomial, ax - r, the remainder is
equal to f(r/a)
When the b in y = a * bˣ less than 1 and greater than 0, this is called
exponential decay
When the b in y = a * bˣ greater than 1, this is called
exponential growth
A town's population grows by 2% every year after 2000, what is the function
f(t) = P(1.02)ᵗ
Vertical shift of a parabola equation
f(x) + k, the graph has shifted "K" units vertically
Cubic graph parent function
f(x) = x³
Horizontal shift of parabola equation
f(x-h), the graph has shifted "H" units horizontally
To find the area of a trapezoid
find the area of the rectangle find the area of triangle (1/2 b*h) add the two areas together
When you multiply or divide a negative number in an inequality
flip the SIGN
When asked to solve for a specific variable, you must
get that variable to one side of the equation
When a polynominal raised to an odd power, the line
goes through the point (X,0)
negative values of A in the quadratic formula for a parabola
graph opens downwards
positive values of A in the quadratic formula for a parabola
graph opens upwards
What is the vertex in vertex form [y = a (x-h)² +k],
h,k
center point of a circle
h,k
The x coordinate of the vertex is
halfway between the two roots
When a polynominal raised to an odd power and the power is over 1, the line
has a slight curve (a point of inflection) as it goes through the point
A parabola in vertex form, y = (x-h)² + k, has shifted...
horizontally "H" units and vertically "K" units to the point (h,k)
the slope can tell you
how many units the y value increases (decreases) as the x values increases
If the arc length is 100°, the arc length
is 5/18 of the circle's circumference bc 100°/360°
if table is two and a half times as long as it is wide, the ratio is:
its length-to-width ratio is 2.5:1
The key for perfect square expressions
look if the middle term is a product of 2
A parabola that is turned into an absolute value function has a graph that
looks the same but the negative values will be moved over the X axis
Model car/ real object or geographical area
m/r = 1/20
With some average problems, you will need to
maximize or minimize a value
When an average/mean question asks for the "least/smallest" value,
maximize the other "unknown" values to the highest given quantity stated in the problem. Ex: An escape room gives ratings from 0 to 100. Maximize all the other unknown ratings, meaning that the average of all ratings is 100.
When an average/mean question asks for the "most/largest" value,
minimize the other "unknown" values to the lowest given quantity stated in the problem.
how to go from percent to decimal
move the percentage two places to the left
How to find P% of a value, x?
multiply the decimal form of the percentage by the value, x.
With percentage you usually
multiply the values
In a triangle when two angles are exactly the same, the third angle __________ and the triangles
must be the same and the triangles must be similar
If you are given a rational function and asked for what values of x makes the function undefined, you
need to find the zeros of the denominator
Absolute value produces a
negative & positive answer
When a system of linear equation has ONE solution, the ratio
of X to Y coefficient for each equation/each lines DOES NOT EQUAL EACH OTHER
In parabolas written in quadratic function, negative coefficients
of the x² term make the graph open downwards
In parabolas written in quadratic function, positive coefficients
of the x² term make the graph open upwards
b²-4ac = 0
one real number zero
In standard form (ax² +bx +c =y), the sign of the X-coordinate of the vertex is
opposite the sign of the product, A*B
you have insert/plug in values, always put
parentheses () around the value
With divided triangles, do ratios between
part-to-part (on the same side) part-to-whole
with fractions, consider if they are asking:
part-to-part or part-to-whole
If you see a radical sign in the original equation,
plug in answers and make sure they're valid
If you see x² or a radical sign in the original equation, you should
plug in the solutions you got to make sure they are valid
With mixture problems, when a quantity is given (10 ounces or grams), you must
plug that number in for any variable
equation for percentage
portion of the total / total = percentage
Similar Triangles have sides that are_______ and angles that are_______
proportional / EQUAL
Answer of polynomial long division is written as
quotient + remainder/ divisor quotient (answer of a division question)
Degrees =
radians * (180/π)
intercepted arc length
radius * # of radians {from the central angle}
arc length =
radius * (central angle in radians)
Vertex Form by Completing the Square
replace the (ax² + bx) part with: A( x + b/2a)² - a(b/2a)² and combine like terms
How to solve: S is what percentage of T?
s/t * 100
Parallel lines have the
same slope, different y intercept
To find the intersection point of two inequality lines,
set the two inequality equations equal to each other and solve for X. Then, Plug X into one of the equations to find Y.
instead of instantly guessing with an answer, you should try to
set up a proportion/ratio for the values
when a question acts to figure out the ratio
set up a proportion/ratio with the quantities in the question
30-60-90 in a equilateral triangle
side across the 90 side/2 across the 30 (side√3)/2 across the 60
cos(x) =
sin(90-x)
when the inequality sign is ≥ or ≤, the line is a
solid line
Intersection points are the
solutions to the system of quadratic & linear equations
If you are given a system of equations with one linear equation and one quadratic question, use
substitution method to solve, set the 2 equations equal to each other
If a problem states that the price of something is raised by 5% and then decrease by 10%
that DOES NOT mean that the price dropped by 5% OVERALL
If you are asked to find the max or min coordinate value in a system of linear inequalities,
that coordinate must be at the intersection point
if you can't figure how to solve a problem that uses decimals, try to convert
the decimals to fractions
In question that discusses ratios, the "if" statement in the question prompt is
the denominator
When "a" in y = a * bˣ is POSITIVE,
the graph will be above the X axis
When "a" in y = a * bˣ is NEGATIVE,
the graph will be below the X axis
If you're told that lines are TANGENT to a circle, know that
the lines intersect the circle at ONE point. At the point, they make a RIGHT ANGLE
When you have an odd number of consecutive odd integers,
the mean -- the median will always equal 0
The value of the discriminant, b² - 4ac, will tell you
the number and types of zeros in a quadratic equation
if a plumber from California is chosen at random, then the denominator is:
the number of plumbers from California
Margin of error applies to ____ and ______
the population and the unit that is being measured
the length along the intercepted arc is EQUAL to
the radius of the circle
When a circle is drawn on the xy plane,
the side lengths can be negative or positive depending on which quadrant they're in radius is always positive
What is "a" in y = a * bˣ
the starting value, y intercept
When two terms with the same base are multiplied by each other,
their exponents will be added together
If the mean is significantly lower than the median, then
there are a few values that weigh less than the majority
If the mean is significantly higher than the median, then
there are a few values that weigh more than the majority
When two lines intersect at one point
they have different slopes and ONE SOLUTION
Two percentages that apply ...
to the SAME reference amount can be added and subtracted
Trapezoid can be divided into a
triangle and rectangle
when there are pictures in the question
try to form connections between the two things
b² - 4ac < 0
two complex number zeros
how to go from decimal to percent
two places to the right
b² - 4ac > 0 (positive)
two real number zeros
Factor Label method looks like:
undesired unit * (desired unit)/ undesired unit
When you do not know the length of the sides of similar triangles
use variables instead of solving
standard deviation is a
way to measure how closely clustered a data set is around the mean
When is the product (AC) method used?
when the A in Ax²+Bx+C is not 1
In parabolas written in quadratic function, x² coefficients with higher absolute values
will make the graph look narrower
In parabolas written in quadratic function, x² coefficients with lower absolute values
will make the graph look wider
In the form "y = a(x+p)(x+q), when a is negative the graph
will open downwards
In the form "y = a(x+p)(x+q), when a is positive the graph
will open upwards
| x + a | > b ???
x + a > b x + a < -b
Quadratic Formula
x = -b ± √(b² - 4ac)/2a
Vertical line equation
x = Number
Sector =
x°/(360° or 2π radians)
arc length (w/ radius) =
x°/360° * (2π * radius)
arc length (w/ circumference) =
x°/360° * (circumference)
Vertex Form
y = a (x-h)² +k
General form of Exponential Equations
y = a * bᶜˣ
If john eats 25% of 8 slices of pizza and George eats 50% of the 8 slices of pizza, can you add the percentages?
yes you can because they ate from the SAME 8 slices of pizza
If a problem tells you something "DECLINES by" 20%, then
you are only paying for 80% (0.8) of the original price.
If a problem tells you something "IS DISCOUNTED BY" 20%, then
you are only paying for 80% (0.8) of the original price.
If a problem tells you something "IS REDUCED by" 20%, then
you are only paying for 80% (0.8) of the original price.
If a problem tells you something "LOSES" 20%, then
you are only paying for 80% (0.8) of the original price.
If a problem tells you something "SHRINKS by" 20%, then
you are only paying for 80% (0.8) of the original price.
If a problem tells you that something "DECREASES by" 20%, then
you are only paying for 80% (0.8) of the original price.
If an item is discounted by 20%, then
you are only paying for 80% (0.8) of the original price.
With questions like "7 + i / 4 - 3i", what can you do
you can multiply the numerator and denominator by the conjugate of the denominator (4+3i)
Arc length (central angle, θ, is in degrees) =
θ × (π/180) × radius
circumference =
π * (diameter)
Area of a circle =
π * r²
distance formula
√(x₂ - x₁)² + (y₂ - y₁)² = D
"At most" & "no greater than"
≤
"at least" "no less than"
≥