x=5-9y
4x+9y=-7
Now use (5-9y) for x in the second equation
4 ( 5 - 9 y ) + 9 y = -7
20 - 36 y + 9 y = -7
I think you can take it from there.
After you get y, go back to the first equation to get x
4x+9y=-7
4 ( 5 - 9 y ) + 9 y = -7
20 - 36 y + 9 y = -7
I think you can take it from there.
After you get y, go back to the first equation to get x