Find the difference quotient of LaTeX:  \displaystyle f(x)=x - 8 .

The difference quotient is LaTeX:  \displaystyle \frac{f(x+h)-f(x)}{h} . Evaluating LaTeX:  \displaystyle f(x+h)=h + x - 8 and expanding gives LaTeX:  \displaystyle f(x+h)=h + x - 8 Evaluating the difference quotient gives LaTeX:  \displaystyle \frac{(h + x - 8)-(x - 8)}{h} Simplifying gives LaTeX:  \displaystyle \frac{h}{h}=1