# Find the Equation Using Point-Slope Formula (-10,-20) , (1,-9)

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Find the slope of the line between and using , which is the change of over the change of .
Slope is equal to the change in over the change in , or rise over run.
The change in is equal to the difference in x-coordinates (also called run), and the change in is equal to the difference in y-coordinates (also called rise).
Substitute in the values of and into the equation to find the slope.
Simplify.
Simplify the numerator.
Multiply by .
Simplify the denominator.
Multiply by .
Divide by .
Use the slope and a given point to substitute for and in the point-slope form , which is derived from the slope equation .
Simplify the equation and keep it in point-slope form.
Solve for .
Multiply by .
Move all terms not containing to the right side of the equation.
Subtract from both sides of the equation.
Subtract from .
List the equation in different forms.
Slope-intercept form:
Point-slope form:
Find the Equation Using Point-Slope Formula (-10,-20) , (1,-9)