You can put this solution on YOUR website! The goal is find a function, g(x), so that -(g(x))^5+6=x. Transforming from this,
-(g(x))^5=-6+x
g(x)^5=x-6
g(x)=(x-6)^(1/5)
To read g(x) more easily,
(That is, the quantity x minus six, to the one-fifth power)
g(x) and f(x) are inverses. f(g(x))=x, and g(f(x))=x