SOLUTION: Solve by elimination: -x+3y=6 x-9y=9

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Question 333165: Solve by elimination:
-x+3y=6
x-9y=9
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
-x+3y=6
x-9y=9 ADD.
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-6y=15
y=15/-6
y=-2.5 ans.
-x+3*-2.5=6
x+-7.5=6
x=6+7.5
x=13.5 ans.
Proof:
13.5-9*-2.5=9
13.5+22.5=9
9=9