Determine whether the lines L1 and L2 passing through the pa

Determine whether the lines L1 and L2 passing through the pairs of points are parallel, perpendicular, or neither. L1: (4, 45), (4, 3) L2: (5, 1), (-2,1/3)

Solution

L1: (4, 45), (4, 3) L2: (5, 1), (-2,1/3)

Find slope of L1 : (3-45)/( -4 -4) = -42/-8 =21/4

slope of L2 : (1/3 +1)/( -2 -5) = 4/3 /-7 = -4/21

If two lines are perpendicular then the product of their slopes =-1

      (21/4)*(-4/21) = -1

Hence the lines are perpendicular