$[2]$ As I said in class, in evaluating a limit$,$ if we na$$vely plug in $x=$a and get $\frac{0}{0},$ we have to do more work. Another situation like this is $"-"$: If you plug in $x=$a and get $[$something going to $][$something going to $],$ then the answer could be $+,-,$ or it could be something finite, and so in this situation we need to do more work to determine which it is$.$

Evaluate $\underset{x2}{lim}(\frac{1}{x-2}-\frac{4}{x^2-4}).$