Answer:
x=-1, y=-3. (-1, -3).
Step-by-step explanation:
x+y=-4
3x-6y=15
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x=-4-y
3(-4-y)-6y=15
-12-3y-6y=15
-12-9y=15
9y=-12-15
9y=-27
y=-27/9
y=-3
x+(-3)=-4
x-3=-4
x=-4+3
x=-1
