Consider the function

a$)$ Simplify the expression for $f(x)$ when

$\frac{x^2+2x-8}{x+4}=$

$$

b$)$ Compute the following limit$.$

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

$$

c$)$ Compute the following limit$.$

$\underset{x-4^{+}}{lim}f(x)=$

$$

d$)$ Find the value of a such that $f$ is continuous at $x=-4.$

Answer: $a=$ A$$