Decide whether the pair of lines is parallel, perpendicular, or neither.
-3x - 6y = 7 18x + 9y = -7
A) parallel
B) perpendicular
C) neither

Question

Quizplus · Accepted Answer

The slopes of the lines are found by converting the equations into slope-intercept form (y = mx + b). For the first equation, 3x - 6y = 7 becomes y = 0.5x - 7/6, so the slope is 0.5. The second equation, 18x + 9y = -7, becomes y = -2x - 7/9, so the slope is -2. Since the slopes are negative reciprocals of each other (0.5 and -2), the lines are perpendicular.

Decide Whether the Pair of Lines Is Parallel, Perpendicular, or Neither