Answer:
x=-3, y=-6. (-3, -6).
Step-by-step explanation:
-9x+7y=-15
-8x+y=18
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y=18-(-8x)=18+8x=8x+18
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-9x+7(8x+18)=-15
-9x+56x+126=-15
47x+126=-15
47x=-15-126
47x=-141
x=-141/47
x=-3
-8(-3)+y=18
24+y=18
y=18-24=-6
x=-3, y=-6.