$\lim _{x \rightarrow-4} \frac{x^{3}+64}{x+4}$ (A) Explain Why Direct Substitution Cannot Be Used to Find

$\lim _{x \rightarrow-4} \frac{x^{3}+64}{x+4}$
(a) Explain why direct substitution cannot be used to find the limit
(b) Find the limit algebraically, if it exists.