Question

"Three of the coordinates of the parallelogram STUV are S(-2,-2), T(7,7) and U(5,15). State the vector ST and hence determine the coordinates of V."

So I've figured out that ST = (9,9), but I don't see how that helps me find V.

Answer 1

If you draw it out, it becomes obvious that the vector ST is the same as UV. If ST has a velocity vector of 9,9 then you can find the coordinates of V.
V = (5-9, 15-9)
(5, 15 are coordinates of U)
V = (-4, 6)