Show that has a jump discontinuity at 7 by calculating the limit as x approaches 7 from the left and from the right.

Show that

$f(x) = \begin{cases}\displaystyle{7x-4}&\text{if}\ x < 7\cr \displaystyle{\frac{5}{x+8}}&\text{if}\ x \ge 7\end{cases}$

has a jump discontinuity at 7 by calculating the limit as x approaches 7 from the left and from the right.

$\displaystyle{\lim_{x\to 7^-}f(x)} =$

$\displaystyle{\lim_{x\to 7^+}f(x)} =$