SOLUTION: x+y=z if x*y=2679 and x-y=10. find z

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Question 783916: x+y=z if x*y=2679 and x-y=10. find z
Answer by xinxin(76) About Me  (Show Source):
You can put this solution on YOUR website!
First solve x and y:
(1).x*y=2679
(2).x-y=10, get x=10+y (3)
From (1),(3), get y^2+10y-2679=0, y=-57 or y=47
Therefore x=-47 or x=57
Because z=x+y, according to the answers above, z=-104 or z=104