Only way I know of to solve this is trial and error. You have to run through all of them to get the right pair :P
(x, y)
Let's try choice A.
2(1.5) = 6 + 3(-1).
3 = 6 + (-3).
3 = 6-3.
3 = 3.
WHOA! We got it on the first try!
Therefore, choice A is a solution for 2y = 6 + 3x