# Precalculus Examples

,

The slope-intercept form is , where is the slope and is the y-intercept.

Find the values of and using the form .

Rewrite in slope-intercept form.

The slope-intercept form is , where is the slope and is the y-intercept.

Combine and .

Rewrite in slope-intercept form.

Find the values of and using the form .

Compare the slopes of the two equations.

Compare the decimal form of one slope with the negative reciprocal of the other slope. If they are equal, then the lines are perpendicular. If the they are not equal, then the lines are not perpendicular.

The equations are perpendicular because the slopes of the two lines are negative reciprocals.

Perpendicular