Finding domain

Question

f(x)=1/x^2-5

Can't remember how to solve, your help is appreciated:-)

Answer 1

If X^2-5 is the denom, then the domain would be all X such that the denom does not equal 0.

So find when x^2-5=0
x=sqrt(5) (Both positive and negative)

So the domain is all real numbers, such that X does not equal +- sqrt (5)