# Find the Slope and Y-Intercept (-15,-11) , (-18,-20)

(-15,-11) , (-18,-20)
Find the value of the slope.
Slope is equal to the change in y over the change in x, or rise over run.
m=change in ychange in x
The change in x is equal to the difference in x-coordinates (also called run), and the change in y is equal to the difference in y-coordinates (also called rise).
m=y2-y1x2-x1
Substitute in the values of x and y into the equation to find the slope.
m=-20-(-11)-18-(-15)
Simplify.
Simplify the numerator.
Multiply -1 by -11.
m=-20+11-18-(-15)
m=-9-18-(-15)
m=-9-18-(-15)
Simplify the denominator.
Multiply -1 by -15.
m=-9-18+15
m=-9-3
m=-9-3
Divide -9 by -3.
m=3
m=3
m=3
Find the value of the y-intercept.
Substitute the value of m into the slope-intercept form of the equation, y=mx+b.
y=(3)⋅x+b
Substitute the value of x into the slope-intercept form of the equation, y=mx+b.
y=(3)⋅(-15)+b
Substitute the value of y into the slope-intercept form of the equation, y=mx+b.
-11=(3)⋅(-15)+b
Rewrite the equation as (3)⋅(-15)+b=-11.
(3)⋅(-15)+b=-11
Multiply 3 by -15.
-45+b=-11
Move all terms not containing b to the right side of the equation.
Add 45 to both sides of the equation.
b=-11+45