Which of the following represents a line perpendicular to the line 4x + 5y = 20?
Show answer & explanation
Correct answer: C
Explanation
Given:
Line = 4x + 5y = 20
By the formula:
At ax + by + c = 0, the slope is m = −a/b
For perpendicular lines, m₁ × m₂ = −1
4x + 5y = 20
5y = −4x + 20
y = (−4/5)x + 4
m₁ = −4/5
m₂ = −1 ÷ (−4/5)
m₂ = 5/4
y = 5x/4 − 3