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 ?
(In reply to
another solution by retiarius)
Solving the second equation for that X gives
√(19)(y+z) + yz = 3, but since y + z = 5√(19), you can replace that.
25  5√(19) +yz = 3
22  5√(19) + yz = 0
This ends up with yz equalling negative; don't know if that's a problem though

Posted by Gamer
on 20031118 18:13:10 