$\sqrt[5]{\frac{128 x^{7} y^{15}}{x y^{7}}}$

Step 1 ：Simplify the expression inside the fifth root: \(\frac{128x^{7}y^{15}}{xy^{7}} = 128x^{6}y^{8}\)

Step 2 ：Take the fifth root of the simplified expression: \(\sqrt[5]{128x^{6}y^{8}} = 2 \cdot 2^{\frac{2}{5}} \cdot (x^6 y^8)^{\frac{1}{5}}\)

Step 3 ：\(\boxed{2 \cdot 2^{\frac{2}{5}} \cdot (x^6 y^8)^{\frac{1}{5}}}\)