# Precalculus Examples

Find the Perpendicular Line
,
Use the slope-intercept form to find the slope.
The slope-intercept form is , where is the slope and is the y-intercept.
Using the slope-intercept form, the slope is .
The equation of a perpendicular line must have a slope that is the negative reciprocal of the original slope.
Find the equation of the perpendicular line using the point-slope formula.
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.
Write in form.
Solve for .