## Precalculus (6th Edition) Blitzer

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.