## Calculus: Early Transcendentals (2nd Edition)

$\lim\limits_{x \to 4}$ $\frac{x^{2}-16}{4-x}$ = $\lim\limits_{x \to 4}$ $\frac{(x-4)(x+4)}{-(x+4)}$ = $\lim\limits_{x \to 4}$ $\frac{(x+4)}{-1}$ = $\lim\limits_{x \to 4}$ -(x+4) = - (4+4) =-8