# functional equations

(i)If $f(x)$ is a polynomial function $f:(0,\infty)\rightarrow(0,\infty)$satisfies the equation $f(f(x))=6x-f(x)$then find $f(17)$
(ii)If $f(x)$ is a polynomial function satisfying the condition such that $f(x^2+1)=(f(x))^2+1$ and that $f(0)=0$ then find $f(34).$