#### Answer

$(x+3)^5$

#### Work Step by Step

Using the properties of radicals, the given expression, $
\sqrt[]{(x+3)^{10}}
,$ simplifies to
\begin{array}{l}
\sqrt[]{\left( (x+3)^5\right)^2}
\\\\=
(x+3)^5
.\end{array}
Note that it is assumed that no radicand was formed by raising negative quantities to even powers. Thus, absolute value bars are not necessary.