It seems like we need more info to solve this problem
Here are a couple of possibilities
y = 1/4 * x
x = -12, y = -3
x = -24, y = -6
Here is a second possibility
y = x + 9
x = -12, y = -3
x = -15, y = -6
So you can see from these examples that we need more information to answer this correctly.