# How do you divide \frac { ( m + 3) ( m - 7) } { m + 5} \div \frac { ( m + 3) ( m - 7) } { m + 5}?

Jan 25, 2018

$1 , \text{ } m \notin \left\{- 5 , - 3 , 7\right\}$

#### Explanation:

Both of these expressions are the exact same.

Therefore, if you divide them, you usually get $1$.

The only exception is when one of the factors in the expression equals zero, because dividing zero by zero is undefined.

This means that $m$ cannot be $- 3$, $7$, or $- 5$, since any of these values would make one of the factors equal to zero.

$1 , \text{ } m \notin \left\{- 5 , - 3 , 7\right\}$