# Precalculus Examples

,

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 the numerator.

Multiply by to get .

Subtract from to get .

Simplify the denominator.

Remove parentheses.

Multiply by to get .

Subtract from to get .

Divide by to get .

The slope of a perpendicular line is the negative reciprocal of the slope of the line that passes through the two given points.

Move the negative in front of the fraction.

Simplify .

Multiply by to get .

Multiply by to get .