2x + y = x - y - 3 = 6 Add 3 to everything 2x + y + 3 = x - y - 3 + 3 = 6 + 3 2x + y + 3 = x - y = 9 2x + y + 3 = 9 2x + y = 6 = x - y Add y to everything 2x + 2y = 6 + y = x Since x = 6 + y substitute every x with 6 + y 2(6 + y) + 2y = x 12 + 4y = x
This is as simplified as I can get and then just place 12 + 4y into every x in the original problem then solve
