The limit below represents the derivative of some function $\displaystyle {f{{\left({x}\right)}}}$ at some number $\displaystyle {a}$.

$\displaystyle \lim_{{{h}\to{0}}}\frac{{{4}{\left({2}+{h}\right)}^{{4}}-{64}}}{{h}}$

State the function and the number:

$\displaystyle {f{{\left({x}\right)}}}$ = Preview Question 6 Part 1 of 2  

$\displaystyle {a}$ =