12.4 Exercise 158

Use technology to evaluate the limit.

Evaluate the limit by hand.

$\begin{matrix}\lim \\ ^{x \rightarrow 1}\end{matrix} f \left(x\right) , \textrm{ }\text{where}\textrm{ }\textrm{ } f \left(x\right) = \left\{\right. \begin{matrix}4 x - 7 & x \neq 1 \\ x^{2} - 4 & x = 1\end{matrix}$

At what value(s) of $x$ is the function below discontinuous?

$f \left(x\right) = \left\{\right. \begin{matrix}4 x - 7 x \neq 1 \\ x^{2} - 4 x = 1\end{matrix}$