Answer
$8\sqrt{2}$.
Work Step by Step
The given expression is
$=\sqrt{128}$
Factor as square terms.
$=\sqrt{64\cdot 2}$
Use product property of square roots.
$=\sqrt{64}\cdot \sqrt{2}$
Use $64=8^2$.
$=\sqrt{8^2}\cdot \sqrt{2}$
Simplify.
$=8\sqrt{2}$.
