3) \frac{18a^{2}b^{3}}{7c^{2}d} : \frac{24ab}{14cd^{2}};

3) \(\frac{18a^{2}b^{3}}{7c^{2}d} : \frac{24ab}{14cd^{2}} = \frac{18a^{2}b^{3}}{7c^{2}d} \cdot \frac{14cd^{2}}{24ab} = \frac{18 \cdot 14 \cdot a^{2}b^{3}cd^{2}}{7 \cdot 24 \cdot abc^{2}d} = \frac{3ab^{2}d}{c}\)

Ответ: \(\frac{3ab^{2}d}{c}\)