Решебник по алгебре 8 класс Макарычев ФГОС Задание 642

 

\[\boxed{\text{642\ (642).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[ax - 2x = a^{3} - 2a^{2} - 9a + 18\]

\[x(a - 2) = a^{2}(a - 2) - 9(a - 2)\]

\[x(a - 2) = (a - 2)\left( a^{2} - 9 \right)\]

\[\ x = a^{2} - 9.\ \]

\[\boxed{\text{642.}\text{\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[\textbf{а)}\ \frac{6}{x} = x\]

\[\left\{ \begin{matrix} y = \frac{6}{x} \\ y = x \\ \end{matrix} \right.\ \]

\[y = \frac{6}{x}\]

\[y = x\]

\[x_{1} = - 2,5;\ \ x_{2} = 2,5\]

\[Ответ:x = \left\{ - 2,5;2,5 \right\}.\]

\[\textbf{б)}\ \frac{6}{x} = - x + 6\]

\[\left\{ \begin{matrix} y = \frac{6}{x} \\ y = - x + 6 \\ \end{matrix} \right.\ \]

\[y = \frac{6}{x}\]

\[y = - x + 6\]

\[x_{1} \approx 1,4;\ \ x_{2} \approx 5\]

\[Ответ:x = \left\{ 1,4;5 \right\}\text{.\ }\]