SOLUTION: Solve each system by addition: x+y=7 x-y=9

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Question 169488: Solve each system by addition:
x+y=7
x-y=9
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
x+y=7
x-y=9
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2x=16
x=16/2
x=8 ans.
8+y=7
y=7-8
y=-1 ans.
Proof:
8-(-1)=9
8+1=9
9=9