Решебник по алгебре 9 класс Макарычев Задание 911

\[\boxed{\text{911\ (911).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ \frac{ab^{2} - 16a}{5b^{3}} \cdot \frac{20b^{5}}{a^{2}b + 4a^{2}} =\]

\[= \frac{a(b - 4)(b + 4)}{5b^{3}} \cdot \frac{20b^{5}}{a^{2}(b + 4)} =\]

\[= \frac{4b^{2}(b - 4)}{a} = \frac{4b³ - 16b²}{2}\]

\[\textbf{б)}\ \frac{7xy}{x^{2} - 4xy + 4y^{2}} \cdot \frac{3x - 6y}{14y^{2}} =\]

\[= \frac{7xy}{(x - 2y)^{2}} \cdot \frac{3(x - 2y)}{14y^{2}} =\]

\[= \frac{3x}{(x - 2y) \cdot 2y} = \frac{3x}{2xy - 4y²}\]

\[\textbf{в)}\ \frac{p^{3} - 125}{8p^{2}} \cdot \frac{4p}{p^{2} + 5p + 25} =\]

\[= \frac{p - 5}{2p}\]

\[\textbf{г)}\ \frac{9m^{2} - 12mn + 4n^{2}}{3m^{3} + 24n^{3}} \cdot \frac{3m + 6n}{2n - 3m} =\]

\[= - \frac{3m - 2n}{m^{2} - 2mn + 4n^{2}} =\]

\[= \frac{2n - 3m}{m² - 2mn + 4n²}\]