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 solution by Charlie)

I agree with SK. If your substituted equation is right, then I get 5y + y(5-5-y) + 5(5-5-y)=3

This substitutes to 5y-(y^2)-5y=3, or y^2=-3, which requires an imaginary value for 3.

Posted by Gamer on 2003-11-17 16:54:52