#### Answer

$8|t|$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
Use the properties of radicals to simplify the given expression, $
\sqrt{64t^2}
.$
$\bf{\text{Solution Details:}}$
Using $\sqrt[n]{x^n}=|x|$ if $n$ is even and $\sqrt[n]{x^n}=x$ if $n$ is odd, then
\begin{array}{l}\require{cancel}
\sqrt{64t^2}
\\\\=
\sqrt{(8t)^2}
\\\\=
|8t|
\\\\=
|8|\cdot|t|
\\\\=
8|t|
.\end{array}