Answer
The difference quotient of the given function is equal to 8.
Work Step by Step
To get the value of $f\left( x+h \right)$, put $x+h$ in place of x, and then substitute in the given expression:
So,
$\begin{align}
& f\left( x+h \right)=8\left( x+h \right)-11 \\
& =8x+8h-11.
\end{align}$
Now,
$\begin{align}
& \frac{f\left( x+h \right)-f\left( x \right)}{h}=\frac{8x+8h-11-8x+11}{h} \\
& =\frac{8h}{h} \\
& =8.
\end{align}$
Therefore, the difference quotient of the given function is equal to 8.