Решебник по алгебре 7 класс Мерзляк Задание 35

\[\boxed{\text{35\ (35).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ 10x + 7 = 8x - 9\]

\[10x - 8x = - 9 - 7\]

\[2x = - 16\]

\[x = - 8\]

\[Ответ:\ x = - 8.\]

\[2)\ 20 - 3x = 2x - 45\]

\[- 3x - 2x = - 45 - 20\]

\[- 5x = - 65\]

\[x = - 65\ :( - 5)\]

\[x = 13\]

\[Ответ:x = 13.\]

\[3)\ 2,7 + 1,9x = 2x + 1,5\]

\[1,9x - 2x = 1,5 - 2,7\]

\[- 0,1x = - 1,2\]

\[x = - 1,2\ :( - 0,1)\]

\[x = 12\ :1\]

\[x = 12\]

\[Ответ:x = 12.\]

\[4)\ \frac{13}{18}x + 13 = \frac{7}{12}x + 8\]

\[\frac{13}{18}x - \frac{7}{12}x = 8 - 13\]

\[x\left( \frac{13^{\backslash 2}}{18} - \frac{7^{\backslash 3}}{12} \right) = - 5\]

\[x\left( \frac{26}{36} - \frac{21}{36} \right) = - 5\]

\[\frac{5}{36}x = - 5\]

\[x = - 5\ :\frac{5}{36} = - 5 \cdot \frac{36}{5}\]

\[x = - 36\]

\[Ответ:x = - 36.\]