\[\boxed{\text{112\ (112).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\frac{48x^{5}}{49y^{4}} \cdot \frac{7y^{2}}{16x^{3}} = \frac{48x^{5} \cdot 7y^{2}}{49y^{4} \cdot 16x^{3}} =\]
\[= \frac{16 \cdot 3 \cdot x^{5} \cdot 7 \cdot y^{2}}{7 \cdot 7 \cdot y^{4} \cdot 16{\cdot x}^{3}} = \frac{3x^{2}}{7y^{2}}\]
\[\textbf{б)}\frac{18m^{3}}{11n^{3}} \cdot \frac{22n^{4}}{9m^{2}} = \frac{18m^{3} \cdot 22n^{4}}{11n^{3} \cdot 9m^{2}} =\]
\[= 4mn\]
\[\textbf{в)}\frac{72x^{4}}{25y^{5}} \cdot \left( - \frac{2,5y^{4}}{27x^{5}} \right) =\]
\[= - \frac{72x^{4} \cdot 2,5y^{4}}{25y^{5} \cdot 27x^{5}} =\]
\[= - \frac{9 \cdot 8 \cdot x^{4} \cdot 25 \cdot 0,1 \cdot y^{4}}{25 \cdot y^{5} \cdot 3 \cdot 9 \cdot x^{5}} =\]
\[= - \frac{0,8}{3xy} = - \frac{8}{30xy} = - \frac{4}{15xy}\]
\[\textbf{г)} - \frac{35ax^{2}}{12b^{2}y} \cdot \frac{8ab}{21xy} =\]
\[= - \frac{35ax^{2} \cdot 8ab}{12b^{2}y \cdot 21xy} =\]
\[= - \frac{5 \cdot 7 \cdot a \cdot x^{2} \cdot 4 \cdot 2 \cdot ab}{3 \cdot 4 \cdot b^{2} \cdot y \cdot 7 \cdot 3 \cdot y} =\]
\[= - \frac{10xa^{2}}{9by^{2}}\]