let coordinates of C be (x, y)
CD = 2AB = 2(sqrt 64) = sqrt( (x-2)^2 + (y + 2)^2)
then sub in the eqn of CD's x or y inside the sqrt( (x-2)^2 + (y
+ 2)^2)
A more effective solution would be...
Vector CD = 2 Vector AB
CO+OD =
2(AO+OB)
OC = OD + 2OA
-2OB
3 steps instead of 2 pages of working...
