Determine whether the lines L1 and L2 passing through the pair of points are parallel , perpendicular , or neither
L1: (-2,-1), (1, 5) and L2: (1, 3), (5,-5)
slope L1 = (5+1)/(1+2) = 6/3 = 2
slope L2 = (-5-3)/(5-1) = -8/4 = -2
Look at your notes or text to see how they are related.
(you can also sketch them and see)