Answer
$ab^{3}$
Work Step by Step
$\frac{\sqrt[4] {a^{6}b^{13}}}{\sqrt[4] {a^{2}b}}$
=$\sqrt[4] \frac{a^{6}b^{13}}{a^{2}b}$
=$\sqrt[4] {a^{6-2}b^{13-1}}$
=$\sqrt[4] {a^{4}b^{12}}$
=$(a^{4})^{\frac{1}{4}}\times(b^{12})^{\frac{1}{4}}$
=$a\times b^{3}$
=$ab^{3}$