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 20031117 16:57:38 