Find each limit$.$ Use $-$ and $$ when appropriate.

$f(x)=\frac{x}{x-5}$

a$.\underset{x{5}^{-}}{lim}f(x)$

b$.\underset{x{5}^{+}}{lim}f(x)$

c$.\underset{x5}{lim}f(x)$

$f(x)=\frac{2x-4}{(x-4{)}^2}$

a$.\underset{x{4}^{-}}{lim}f(x)$

b$.\underset{x{4}^{+}}{lim}f(x)$

c$.\underset{x4}{lim}f(x)$

$f(x)=\frac{x^2+x-2}{x-1}$

a$.\underset{x{1}^{-}}{lim}f(x)$

b$.\underset{x{1}^{+}}{lim}f(x)$

c$.\underset{x1}{lim}f(x)$

$f(x)=\frac{x^2-3x+2}{x+2}$

a$.\underset{x-2^{-}}{lim}f(x)$

b$.\underset{x-2^{+}}{lim}f(x)$

c$.\underset{x-2}{lim}f(x)$

Find the limit of each of the following as $x$ approaches $$ and as $x$ approaches $-.$

$p(x)=15+3x^2-5x^3$

$p(x)=9x^2-6x^4+7x$

$p(x)=5x+x^3-8x^2$

$p(x)=x^4+2x^5-11x$

$p(x)=x^2+7x+12$

$p(x)=-2x^4+3x^2-1$