>On the first comment, it has to be possible. Think about
>it:
>x^(10-x) has to have a maximum value. With it notated
>(x,x^(10-x)):
>1,1
>2,256
>3,2187
>4,4096
>5,3125
>6,1296
>7,343
>8,64
>9,9
>10,1
>With 0<x<1, the value will always be between 0 and 1. Oh!!!
> Maybe this will help. X cannot be negative. With my
>original function,
>x^(y-x), 0=<x=<y. I hope you guys can see where I'm going
>with this now...
>Bye
>Brad

Hmm, the solution above only applied for integral, Which is not stated in the problem. In addition, it's done by trial and error ??? =.='
And the solution provided by JJ is way to complex for me ( a grade 12 student, lol).
That being said, this kind of problem is way too ambiguity ( or you'd prefer: general)for high school or even first year university, so you'd better not fooling around with it. Come back when you have a specific number for y :P.
Regards.