Hello Everyone, I have a small question, any help woulkd be appreciated

This is my first time using latex so excuse my errors if any are made

$\displaystyle f(x)=\frac{1}{\sqrt x^2-16}$

The question is too find the domain and range

EDIT: The Square root is meant to go on the x^2 and the -16 ($\displaystyle \sqrt {x^2-16}$) Like This