SOLUTION: (x+y-z)(x+y+z)

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Question 813549: (x+y-z)(x+y+z)
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
That is cute
Think of it as (a-b)*(a+b) which we know =a^2-b^2
where x+y=a z=b
a^2-b^2
(x+y)^2-z^2
Now expand (x+y)^2
x^2+2xy+y^2-z^2