If x, y and z are real numbers such that: x + y + z = 5 and xy + yz + zx = 3, what is the largest value that x can have ?

If x = 5, y = -z. This means yz is negative (assuming y and z are real), and since yx = -zx, 3 = something negative. This is a contradiction, so it doesn't work.

I can't find a flaw yet in Charlie's solution; is this just extraneous solutions again?

Posted by Gamer on 2003-11-17 16:57:38