Решебник по алгебре 7 класс Мерзляк Задание 54

\[\boxed{\text{54\ (54).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ 3ax = 12 - x;\ \ \ \ x = - 9\]

\[3 \cdot ( - 9) \cdot a = 12 - ( - 9)\]

\[- 27a = 12 + 9\]

\[- 27a = 21\]

\[a = - \frac{21}{27}\]

\[a = - \frac{7}{9}\]

\[Ответ:при\ a = - \frac{7}{9}.\]

\[2)\ (5a + 2) \cdot x = 8 - 2a;\ \ \ \ \]

\[\ x = 2\]

\[2 \cdot (5a + 2) = 8 - 2a\]

\[10a + 4 = 8 - 2a\]

\[10a + 2a = 8 - 4\]

\[12a = 4\]

\[a = \frac{4}{12}\]

\[a = \frac{1}{3}\]

\[Ответ:при\ a = \frac{1}{3}.\]