Chapter 7 - Rational Functions - 7.3 Multiplying and Dividing Rational Expressions - 7.3 Exercises - Page 580: 24

$= \frac{20a^{2}}{9bc^{2}}$

$\frac{10a^{3}}{6b^{2}c^{4}} \div \frac{15a}{20bc^{2}}$ $= \frac{10a^{3}}{6b^{2}c^{4}} \times \frac{20bc^{2}}{15a}$ $= \frac{200a^{3}bc^{2}}{90ab^{2}c^{4}}$ $= \frac{20a^{3}bc^{2}}{9ab^{2}c^{4}}$ $= \frac{abc^{2}(20a^{2})}{abc^{2}(9bc^{2})}$ $= \frac{20a^{2}}{9bc^{2}}$