Chapter 1, Problem 12RE

In each part, find ${\lim }_{x\to a}f\left(x\right),$ if exists, where $a$ is replaced by $0,5^{+},-5^{-},-5,5,-\infty ,$ and $+\infty$ .

(a) $f\left(x\right)=\sqrt{5-x}$

(b) $f\left(x\right)=\left\{\begin{array}{cc}\left(x-5\right)/\left|x-5\right|,& x\ne 5\\ 0,& x>5\end{array}\right.$