Find the difference quotient of $LaTeX: \displaystyle f(x)=- 7 x^{2} + 10 x + 4$ .

The difference quotient is $LaTeX: \displaystyle \frac{f(x+h)-f(x)}{h}$ . Evaluating $LaTeX: \displaystyle f(x+h)=10 h + 10 x - 7 \left(h + x\right)^{2} + 4$ and expanding gives $LaTeX: \displaystyle f(x+h)=- 7 h^{2} - 14 h x + 10 h - 7 x^{2} + 10 x + 4$ Evaluating the difference quotient gives $LaTeX: \displaystyle \frac{(- 7 h^{2} - 14 h x + 10 h - 7 x^{2} + 10 x + 4)-(- 7 x^{2} + 10 x + 4)}{h}$ Simplifying gives $LaTeX: \displaystyle \frac{- 7 h^{2} - 14 h x + 10 h}{h}=- 7 h - 14 x + 10$