I have to find the domain of
______
h(x) = √x^2-9

I know that x^2-9 ≥ 0
so x≥±3
and so x≥3 works but I also guessed x values for when x≤-3 and they work too. How do I find x≤-3 algebraically without having to guess if these values work?

Question

I have to find the domain of
             ______
h(x) = √x^2-9

I know that x^2-9 ≥ 0
so x≥±3
and so x≥3 works but I also guessed x values for when x≤-3 and they work too. How do I find x≤-3 algebraically without having to guess if these values work?

gorv · Answer

anything inside the root should be >=0 to calculate the sauare root
so x^2-9>=0
now find lol

anonymous · Answer

yeah so it would be x≥3 but it doesn't give me x≤-3 which also works

popitree · Answer

-3>=x >=3

anonymous · Answer

x>=3 and x<=-3*

anonymous · Answer

oh ok never mind

gorv · Answer

x^2>=9
this will give x<=-3
or x>=3