# Question #a5656

Feb 6, 2017

$\mathbb{C} - \left\{1\right\}$

#### Explanation:

You want the domain of ${f}^{-} 1 \left(x\right) = y$,

$x = \frac{y - 5}{y + 5}$

$x y + 5 x = y - 5$

$x y - y = - 5 x - 5$

$y = \frac{- 5 x - 5}{x - 1} = - 5 \frac{x + 1}{x - 1}$

We may divide by $x - 1$ if and only if $x \ne 1$.