Ok I know that to find the slope of a line the formula is $\displaystyle m=\frac {y_2-y_1}{x_2-x_1}$, but when I try to solve for it I get $\displaystyle \frac {f(2+h)-4}{h}$. Is that right?Find the slope of the line joining $\displaystyle (2,4)$ and $\displaystyle (2+h, f(2+h))$ in terms of the nonzero number $\displaystyle h$