Lesson 8 - Equations of Lines in the Coordinate Plane

Find the slope of ( -1,2 ) ,(4,-2)

-4/5

Equation when slope is 2 and coordinates (-1,5)

1. y-y1=m(x-x1) 2.y-5=2(x-(-1) 3.y-5=2(x-1) 4.y-5=2x-2 5.y-5=2x-2 +5 +5 y=2x-2 or y=2x+7 (more simplified )

Find the slope of (4,0), (4,-2)

2/0 (undefined )

Write the 2 points using an equation (-2,-1), (3,5 )

5-(-1)/3-(-2) =6/5 y-y1=m(x-x1) y-(-1)=6/5(x-5)

Definition of slope of a line

Measuring the steepness

What type of line is this ?

Negative line

What type of line is this ?

Positive line

What type of line is this ?

Undefined Line

Equation for horizontal and vertical line of (2,4)

X (horizontal )axis =2 and Y (vertical ) axis =4

What type of line is this ?

Zero line

Point Intercept form

y-y1=m(x-x1)

Equation of slope

y2-y1/x2-x1 rise/run (vertical /horizontal)

Equation when the slope -3 and coordinates (-1,4)

y=-3x+1 or y=-3x+5 (more simplified )

Equation when the slope is 3 and y is -5

y=3x-5 or y=3x+-5

Equation when the slope is 4 and y is 5

y=4x+5

Slope-intercept form

y=mx+b