Answer:
x=0, y=-2
Explanation:
Because 9y appears twice in both equations, you can subtract the equations to eliminate the y variable so you can solve for x:
-7x + 9y = -18
-(4x + 9y = -18)
__________
-11x = 0
x = 0
Since we know x=0, then we plug it back into one of the equations to get the value of y:
-7x + 9y = -18
-7(0) + 9y = -18
0 + 9y = -18
9y = -18
y = -2
Therefore, x=0, and y=-2