\[\boxed{\text{135\ (135).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\textbf{а)}\ \frac{3x^{2}}{5y^{3}}\ :\frac{9x^{3}}{2y^{2}} \cdot \frac{5y}{3x} =\]
\[= \frac{3x^{2}}{5y^{3}} \cdot \frac{2y^{2}}{9x^{3}} \cdot \frac{5y}{3x} =\]
\[= \frac{3x^{2} \cdot 2y^{2} \cdot 5y}{5y^{3} \cdot 9x^{3} \cdot 3x} = \frac{2}{9x^{2}}\]
\[\textbf{б)}\ \frac{7p^{4}}{10q^{3}} \cdot \frac{5q}{14p^{2}}\ :\frac{3p}{4q^{4}} =\]
\[= \frac{7p^{4}}{10q^{3}} \cdot \frac{5q}{14p^{2}} \cdot \frac{4q^{4}}{3p} =\]
\[= \frac{7p^{4} \cdot 5q \cdot 4q^{4}}{10q^{3} \cdot 14p^{2} \cdot 3p} = \frac{pq^{2}}{3}\]