Solve through linear combination
4x+9y=9
+ 2x-9y=-63
6x = -54
So, you get the equation 6x=54, and by diving by 6 on each side of the equation you find that x=9
Plug this into one of the original equations to find y.
4(9)+9y=9
36+9y=9
9y=-27
y=-3
Now we know that x=9 and y=-3, so the solution to this system of equations is (9,-3)