Question

A line has a slope of Negative four-fifths. Which ordered pairs could be points on a line that is perpendicular to this line? Select two options.

(–2, 0) and (2, 5)
(–4, 5) and (4, –5)
(–3, 4) and (2, 0)
(1, –1) and (6, –5)
(2, –1) and (10, 9)

Answer 1

Perpendicular slope = 5/4 (since (-4/5)·(5/4) = -1).

Compute slopes:
- (–2, 0) to (2, 5): (5−0)/(2−(−2)) = 5/4 ✓
- (–4, 5) to (4, −5): (−5−5)/(4−(−4)) = −10/8 = −5/4 ✗
- (−3, 4) to (2, 0): (0−4)/(2−(−3)) = −4/5 ✗
- (1, −1) to (6, −5): (−5−(−1))/(6−1) = −4/5 ✗
- (2, −1) to (10, 9): (9−(−1))/(10−2) = 10/8 = 5/4 ✓

Answers: (–2, 0) and (2, 5); (2, −1) and (10, 9).