#### Answer

$12i\sqrt2$

#### Work Step by Step

Factor the radicand so that one factor is a perfect square then simplify to obtain:
$=\sqrt{144(-2)}
\\=\sqrt{12^2(-2)}
\\=12\sqrt{-2}$
Factor out $-1$ in the radicand to obtain:
$=12\sqrt{-1(2)}$
Since $\sqrt{-1} = i$, bring out the square root of $-1$, which is $i$, to obtain:
$=12i\sqrt2$