#### Answer

Domain: X is on the interval ($-\infty$, -1) U (-1, 1) U (1, $\infty$)

#### Work Step by Step

A denominator cannot be zero, so the domain is all real numbers except the x value where the denominator is 0.
In this problem the denominator is $x^{2}$ - 1, so:
$x^{2}$ - 1 = 0
This can be factored into:
(x + 1)(x - 1) = 0
x = -1, 1
Therefore, the domain is all real numbers except where x = -1 and x = 1.