#### Answer

$\sqrt[4] {a^{3}b^{2}}$

#### Work Step by Step

$\sqrt[12] {a^{9}b^{6}}$
=$\sqrt[12] {a^{9}}\times\sqrt[12] {b^{6}}$
=$(a^{9})^{\frac{1}{12}}\times(b^{6})^{\frac{1}{12}}$
=$a^{\frac{3}{4}}\times b^{\frac{2}{4}}$
=$\sqrt[4] {a^{3}}\times\sqrt[4] {b^{2}}$
=$\sqrt[4] {a^{3}\times b^{2}}$
=$\sqrt[4] {a^{3}b^{2}}$