Решение:
\(\frac{\sqrt{81} \sqrt{b}}{\sqrt[14]{b}} = \frac{9 \sqrt{b}}{\sqrt[14]{b}} = 9 \cdot \frac{b^{1/2}}{b^{1/14}} = 9 \cdot b^{\frac{1}{2} - \frac{1}{14}} = 9 \cdot b^{\frac{7}{14} - \frac{1}{14}} = 9 \cdot b^{\frac{6}{14}} = 9 \cdot b^{\frac{3}{7}} = 9 \sqrt[7]{b^3}\)
Ответ: \(9 \sqrt[7]{b^3}\)