Answer
The domain is the set of real numbers less than or equal to $1$.
Work Step by Step
The given function is
$h(x)=\sqrt{-x+1}$
The radicand cannot be negative.
So, $-x+1$ is greater than or equal to zero.
$\Rightarrow -x+1\geq 0$
Add $x$ to each side.
$\Rightarrow -x+1+x\geq 0+x$
Simplify.
$\Rightarrow 1\geq x$
Hence, the domain is the set of real numbers less than or equal to $1$.
