Write the composite function in the form f(g(x)). [Identify the inner function u =f(u).] (Use non-identity functions for f(u) and g(x).)g(x) and the outer function y y=\left(9-x^{5}\right)^{6} (f(u), g(x))= \text

{ Find the derivative } \frac{d y}{d x} \text { . }