How to find the equation of a perpendicular line - GRE Quantitative Reasoning

Card 1 of 40

0
Didn't Know
Knew It
0
1 of 2019 left
Question

Which of the following equations represents a line perpendicular to 3x + 4y = 5?

Tap to reveal answer

Answer

Perpendicular lines have opposite and reciprocal slopes. Therefore, let us find the slope of our line and appropriately modify it to find the perpendicular line. To find the slope of our line, remember that in the slope-intercept form (y = mx + b), m represents the slope.

3x + 4y = 5 => 4y = 5 - 3x => y = (-3/4)x + 5/4

Therefore, the slope of our line is -3/4. The perpendicular to this would be 4 / 3. Therefore, only y = (4/3)x - 15 is perpendicular.

← Didn't Know|Knew It →