I've left enough gaps for you to lay some claim to the solution for yourself:

On the one hand, X(-3, 1, 4) + Y(6, - 6, -5) = (-3X + 6Y, ...........)

But on the other hand X(-3, 1, 4) + Y(6, - 6, -5) = (-36, 32, 33).

Therefore:

-3X + 6y = -36 .... (1)

..... (2)

....... (3)

Equations (1), (2) and (3) are to be solved simultaneously for X and Y. Choose two of the equations and solve. Check that the resulting solutions satisfy the third equation (if they didn't, then there'd be no solution at all - all three equations have to be satisfied).