# How do you simplify (64-c^2)/(c^2-7c-8) and what are the ecluded values fot he variables?

Oct 16, 2016

this expression can be simplified to $- \frac{c + 8}{c + 1}$ with restrictions of $c \ne 8$ and $c \ne - 1$.

#### Explanation:

Factor.

$= - \frac{{c}^{2} - 64}{{c}^{2} - 7 c - 8}$

$= - \frac{\left(c + 8\right) \left(c - 8\right)}{\left(c - 8\right) \left(c + 1\right)}$

$= - \frac{c + 8}{c + 1}$

As for the excluded values, these are found by setting the denominator of the initial expression to $0$ and solving for the variable.

${c}^{2} - 7 c - 8 = 0$

$\left(c - 8\right) \left(c + 1\right)$

$c = 8 \mathmr{and} - 1$

Hence, $c \ne 8$ and $c \ne - 1$.

Hopefully this helps!