Answer
The domain of the function is the set of real numbers greater than or equal to $4$.
Work Step by Step
$y=\sqrt 2x-8$
The radicand cannot be negative.
$ 2x-8 \geq 0$
$2x \geq 8$
$x \geq 4$
The domain of the function is the set of real numbers greater than or equal to $4$.
