1) Plug in for x into the equation
4(2y-3)+9y=-63
8y-12+9y
17y-12=-63
y=-3
2) Plug in for y into the equation
4x+9(-3)=-63
4x-27=-63
+27. +27
4x=-36
-36/4= -9
x=-9
(-9,-3)
Now check by pluging in for x and y and see if the equation is true.
4(-9)+9(-3)
-36 + -27= -63