Complete parts $($a$)$ and $($b$)$ below for the following function f $.$

$f(x)=5x^{2}6$

a$.$ Use limits to find the derivative function $f^{\text{'}}.$

Identify the limit that should be evaluated in order to find the derivative function $f^{\text{'}},$ using $h$ and not using $f$ in your answer.

$f^{\text{'}}(x)=\underset{h0}{lim}$