Answer
See graph (red).
domain $(-\infty, 2]$, range $[0,\infty)$.
Work Step by Step
Step 1. To obtain the graph of $f(x)=4\sqrt {2-x}=4\sqrt {-(x-2)}$ from $y=\sqrt x$, shift the curve 2 units to the right, reflect across the y-axis, then stretch vertically by a factor of 4. See graph (red).
Step 2. We can find the domain $(-\infty, 2]$ and the range $[0,\infty)$.
