You will find a graphing calculator useful.
Let $f(x)=\left(x^{2}-9\right) /(x+3)$
a. Make a table of the values of $f$ at the points $x=-3.1$ $-3.01,-3.001,$ and so on as far as your calculator can go. Then estimate $\lim _{x \rightarrow-3} f(x) .$ What estimate do you arrive at if you evaluate $f$ at $x=-2.9,-2.99,-2.999, \ldots .$ instead?
b. Support your conclusions in part (a) by graphing $f$ near $c=-3$ and using Zoom and Trace to estimate $y$ -values on the graph as $x \rightarrow-3$
c. Find $\lim _{x \rightarrow-3} f(x)$ algebraically, as in Example 7