# What is the domain and range of y = sqrt(x-4)?

The domain is such that the argument $x - 4 \ge 0$
This means that $x \ge 4$ or domain = $\left[4 , \infty\right)$
The range: $y$ can only be non-negative, but has no limits at the upper side, so range = $\left[0 , \infty\right)$