Answer
$p^{2}qr^{11}\sqrt[4] (p^{3}r)$
Work Step by Step
$\sqrt[4] (p^{11}q^{4}r^{45})=\sqrt[4] (p^{8}\times q^{4}\times r^{44}\times p^{3}r)=\sqrt[4] (p^{8})\times \sqrt[4] (q^{4}) \times \sqrt[4] (r^{44})\times \sqrt[4] (p^{3}r)=p^{2}qr^{11}\sqrt[4] (p^{3}r)$
$\sqrt[4] (p^{8})=p^{2}$, because $(p^{2})^{4}=p^{2\times4}=p^{8}$
$\sqrt[4] (q^{4})=q$, because $(q)^{4}=q^{4}$
$\sqrt[4] (r^{44})=r^{11}$, because $(r^{11})^{4}=r^{11\times4}=r^{44}$
