Question 1015557
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x-3y=9 
x=3y+9 . Use this to substitute for x in the other equation.
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7x-8y=-2
7(3y+9)-8y=-2
21y+63-8y=-2
13y+63=-2
13y=-65
y=-5
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x-3y=9
x-3(-5)=9
x-(-15)=9
x+15=9
x=-6
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ANSWER: (-6,-5)
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CHECK:
7x-8y=-2
7(-6)-8(-5)=-2
-42-(-40)=-2
-42+40=-2
-2=-2
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