2.1 - 2.3 Review
How do you find the constant of variation given a set of ordered pairs?
Divide the y value by the x value k = y/x
Parallel lines have slopes that are ____________.
Equal
How do you use the vertical line test to determine if a graph is a function?
If any vertical line drawn through the graph hits more than one point on the graph, it is not a function.
What is the slope of all vertical lines?
No slope or undefined slope
What point is always on a direct variation graph?
The origin or (0, 0)
How can you tell if a set of ordered pairs is a function?
There is no repeated x value
Find the slope of the line y - 8 = -3(x + 4)
This equation is in point slope form. The slope is the value in the m position. The slope in this equation is -3.
Find the slope of the line that passes through these 2 points (-6,2) (-6-9)
Undefined since there is 0 in the denominator
Find the variation constant if the direct variation equation is 7x + 8y = 0
k = -7/8 Put the equation in y = kx form by solving for y. This gives you y = -7/8x
Perpendicular lines have slopes that are ________.
opposite reciprocals
Write the equation of a vertical line that goes through the point (-4, -1).
x = -4 Graph the point. Draw a vertical line through it. Notice that every point on the line has an x value of -4.
Find the x intercept of the line 2x + 4y = 8
x = 4 or (4, 0) Let y = 0 and solve for x.
What is point-slope form?
y - y₁ = m (x - x₁)
Find the y-intercept of the line 9x + 3y = -36
y = -12 or (0, -12) Let x = 0 and solve for y.
Write a direct variation equation in the form y = kx for the function that passes through the point (-3, 9).
y = -3x Find k by dividing y by x
Write the equation of a horizontal line that goes through the point (8 , 2).
y = 2 Graph the point. Draw a horizontal line through it. Notice that every point on that line has a y value of 2.
Write the equation of the line that is parallel to y = 4x - 1 and goes through the point (-2 , 3),
y = 4x + 11 Start in point slope form. Since the line is parallel to the given line, use the same slope, which is 4 in this case.
What is the form of a direct variation equation?
y = kx
What is slope-intercept form?
y = mx + b
What is the slope of all horizontal lines?
0 slope
Find the slope of the line that passes through these 2 points (8, 6) and (2, 5)
1/6 Use the slope formula
What is standard form?
Ax + By = C
Find the slope of the line 8x + 4y = 32
Divide the opposite of the A value by the B value. Slope = -2