## Precalculus (6th Edition) Blitzer

$(-\infty, 18]$
Step 1. To find the domain for $h(x)=\sqrt {36-2x}$, let $36-2x\geq0$; we have $2x\leq36$ and $x\leq18$ Step 2. Thus, the domain is $(-\infty, 18]$