Find the difference quotient of $LaTeX: \displaystyle f(x)=7 x - 5$ .

The difference quotient is $LaTeX: \displaystyle \frac{f(x+h)-f(x)}{h}$ . Evaluating $LaTeX: \displaystyle f(x+h)=7 h + 7 x - 5$ and expanding gives $LaTeX: \displaystyle f(x+h)=7 h + 7 x - 5$ Evaluating the difference quotient gives $LaTeX: \displaystyle \frac{(7 h + 7 x - 5)-(7 x - 5)}{h}$ Simplifying gives $LaTeX: \displaystyle \frac{7 h}{h}=7$