Answer
$$\frac{x-7}{\left(x+4\right)^2\left(x+1\right)}$$
Work Step by Step
Performing the given operation and then factoring and combining like terms to simplify, we find:
$$\frac{\frac{x^2-11x+28}{x^2+5x+4}}{x^2-16}\\ \frac{x^2-11x+28}{\left(x^2+5x+4\right)\left(x^2-16\right)}\\ \frac{\left(x-4\right)\left(x-7\right)}{\left(x+4\right)^2\left(x+1\right)\left(x-4\right)}\\ \frac{x-7}{\left(x+4\right)^2\left(x+1\right)}$$
