Answer
Domain: $x\leq 7$
Range: $y\geq 0$
Work Step by Step
Given \begin{equation}
h(x)=\sqrt{7-x}.
\end{equation} The radicand of a radical function must be positive. This means that we must have $$7-x\geq 0\implies 7\geq x\implies x\leq 7.$$ Also, we see that the function's value must satisfy $y\geq 0$ because $\sqrt{7-x}\geq 0$.
We got \begin{equation}
\begin{aligned}
\textbf{Domain :}\quad & x\leq 7\\
\textbf{Range :}\quad & y\geq 0\\\\
\end{aligned}
\end{equation}
