Question

What is the domain and range of `f(x) = x^2 - 12`?

Answer 1

The domain is the set of real numbers so `D(f)=R`.

The range can be found by noticing that

`f(x)+12=x^2>=0=>f(x)+12>=0=>f(x)>=-12`

so the range is `R(f)=[-12,+oo)`