Answer
$x\lt-1$ or $x\gt1$
Work Step by Step
We know that $(x-k)^2\geq0$ for all $k$.
So here for the inequality to be true, $x^2-1\gt0\\x^2\gt1$ (because if it is equal to $0$ the fraction is undefined)
$x^2\gt1$ when $x\lt-1$ or $x\gt1$
So the solution is $x\lt-1$ or $x\gt1$
