Find a Formula for the Slope of the Graph Of f

Multiple Choice

Find a formula for the slope of the graph of $f$ at the point $( x , f ( x ) )$ .Then use it to find the slope at the given point. $f ( x ) = x ^ { 3 } , \quad ( - 5 , - 125 )$

A) $\begin{array} { l } m = 3 x ^ { 2 } \\\text { At } ( - 5 , - 125 ) , m = 75\end{array}$
B) $\begin{array} { l } m = - 3 x ^ { 2 } \\\text { At } ( - 5 , - 125 ) , m = 75\end{array}$
C) $\begin{array} { l } m = 3 x ^ { 2 } \\\text { At } ( - 5 , - 125 ) , m = - 75\end{array}$
D) $\begin{array} { l } m = 3 x \\\operatorname { At } ( - 5 , - 125 ) , m = 75\end{array}$
E) $\begin{array} { l } m = - 3 x ^ { 2 } \\\text { At } ( - 5 , - 125 ) , m = - 75\end{array}$