12.3 Exercise 24

Determine why the function $f$ is discontinuous at a given point $a$ on the graph. State which condition fails.

$f \left(x\right) = \left\{\right. \begin{matrix}\frac{x^{2} - 9}{x + 3} , & x < - 3 \\ x - 9 , & x = - 3 \\ \frac{1}{x} , & x > - 3\end{matrix} \textrm{ }\textrm{ }\textrm{ }\textrm{ } a = - 3$