# 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 .

Add and .

Simplify the denominator.

Multiply by .

Add and .

Dividing two negative values results in a positive value.

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

Multiply the numerator by the reciprocal of the denominator.

Multiply by .

Multiply by .