What is the value of y so that AB with endpoints A(1, y) and B(6, −1) is parallel to CD with points C(1,2) and D(-4,-2)??
+130511 Let's find the slope between C and D =
[- 2 - 2] / [-4 - 1] = -4 / - 5 = 4 / 5
So.....since AB is parallelt to CD, it will have the same slope....and we have
[ - 1 - y ] / [6 - 1] = 4 / 5 simplify
[-1 - y ] / 5 = 4 / 5 multiply both sides by 5
-1 - y = 4 add 1 to both sides
-y = 5 multiply both sides by -1
y = -5
