Answer:
x = 3, y = -1
Step-by-step explanation:
1) x - y = 4
2x + y = 5
2) 3x = 9
3) x = 3 (9/3)
4) 3 - y = 4
(x - y = 4)
5) -y = 1 (4-3)
6) y = -1
