Answer:
(x, y)=(4,-8)
Step-by-step explanation:
9x+y=28
3x+3y=-12 /:(-3)
9x+y=28.......(1)
-x-y=4......(2)
(1)+(2): 8x=32
x=32/8
x=4
9*4+y=28
36+y=28
y=28-36
y=-8
(x, y) =(4,-8)
