Compute and simplify the difference quotient [f(x + h) - f(x)]/h.
f(x) =

Compute and simplify the difference quotient for what?

You have the general form.

The definition of a derivative is given by

f'(x)=\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}.

But we need an f(x) to evaluate.