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

The domain is the set of real numbers so $D \left(f\right) = R$.
$f \left(x\right) + 12 = {x}^{2} \ge 0 \implies f \left(x\right) + 12 \ge 0 \implies f \left(x\right) \ge - 12$
so the range is $R \left(f\right) = \left[- 12 , + \infty\right)$