Determine whether the lines L1 and L2 passing through the pairs of points are parallel, perpendicular or neither.

Question

1) L1: (0,-1), (5,9)

L2: (0,3), (4,1)

2) L1: (3,6), (-6,0)

L2: (0,-1), (5, 7/3)

Answer 1

1) Slope of L1 = (9--1)/(5-0) =2

Slope of L2 = (1-3)/(4-0) = -1/2

L1 and L2 are perpendicular because the product of their slopes is -1

2) Slope of L1 = (0-6)/(-6-3) = 2/3

Slope of L2 = (7/3 --1)/(5-0) = 2/3

L1 and L2 are parallel because their slopes are equal