If we know that x + y = z, can we find out what xy = ?(adsbygoogle = window.adsbygoogle || []).push({});

This is what I did. Say z = 5

x + y = z

x + y = 5

y = 5 - x

xy = ???

x(5 - x) = ???

5x - 2x = ??? (Since 2x = x^2)

3x = ???

xy = 3x

x = xy / 3

1 = y / 3 (divided by x)

y = 3

and since

x + y = 5

x + 3 = 5

x = 2

So

xy = (2)(3)

xy = 6.

Please tell me if this is valid. Thanks

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# Is there a way to solve this?

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