Answer
$x^{9}\sqrt[5] (x^{4})$
Work Step by Step
$\sqrt[5] (x^{49})=\sqrt[5] (x^{45}\times x^{4})=\sqrt[5] (x^{45})\times \sqrt[5] (x^{4})=x^{9}\sqrt[5] (x^{4})$
We know that $\sqrt[5] (x^{45})=x^{9}$, because $(x^{9})^{5}=x^{9\times5}=x^{45}$.