$\frac{1}{x^2+8 x+16} +\frac{1}{x+4} =($ $)/($ $)$.
$\frac{1}{x^2+8 x+16}-\frac{1}{x+4} =($ $)/($ $)$.
$\frac{1}{x^2+8 x+16}\times \frac{1}{x+4} =($ $)/($ $)$.
$\frac{1}{x^2+8 x+16}\div\frac{1}{x+4} =($ $)/($ $)$.
Hint: Think about the binomial formulas