Решебник по математике 6 класс Ерина Виленкин рабочая тетрадь Часть 1, 2 Часть 2 | Страница 77

\[Стр.\ 77.\]

\[\boxed{\mathbf{4.}}\]

\[\textbf{б)} - 3x = 21\]

\[x = 21\ :( - 3)\]

\[x = - 7.\]

\[\textbf{в)}\ 7x = - 56\]

\[x = - 56\ :7\]

\[x = - 8.\]

\[\textbf{г)}\ 5x - 3 = 12\]

\[5x = 12 + 3\]

\[5x = 15\]

\[x = 15\ :5\]

\[x = 3.\]

\[\textbf{д)} - 4x + 1 = 13\]

\[- 4x = 13 - 1\]

\[- 4x = 12\]

\[x = 12\ :( - 4)\]

\[x = - 3.\]

\[\textbf{е)} - x + 9 = 16\]

\[- x = 16 - 9\]

\[- x = 7\]

\[x = - 7.\]

\[\textbf{ж)}\ 6x - 14 = 1 + 3x\]

\[6x - 3x = 1 + 14\]

\[3x = 15\]

\[x = 15\ :3\]

\[x = 5.\]

\[\textbf{з)}\ 7x + 17 = x - 1\]

\[7x - x = - 1 - 17\]

\[6x = - 18\]

\[x = - 18\ :6\]

\[x = - 3.\]

\[\textbf{и)} - 8x + 3 = - x + 24\]

\[- 8x + x = 24 - 3\]

\[- 7x = 21\]

\[x = 21\ :( - 7)\]

\[x = - 3.\]

\[к)\ 5 \cdot (x - 2) - 4 = 6x + 7\]

\[5x - 10 - 4 = 6x + 7\]

\[5x - 6x = 7 + 14\]

\[- x = 21\]

\[x = - 21.\]

\[л)\ 4 \cdot (6x + 11) - 14 =\]

\[= 2 \cdot (2x - 5)\]

\[24x + 44 - 14 = 4x - 10\]

\[24x - 4x = - 10 - 30\]

\[20x = - 40\]

\[x = - 40\ :20\]

\[x = - 2.\]

\[м)\ 2 \cdot (x + 1) - 8 = x + 4\]

\[2x + 2 - 8 = x + 4\]

\[2x - x = 4 + 6\]

\[x = 10.\]

\[н)\ 8 \cdot (2x - 3) + 7 =\]

\[= 4 \cdot (2 - x) - 1\]

\[16x - 24 + 7 = 8 - 4x - 1\]

\[16x + 4x = 7 + 17\]

\[20x = 24\]

\[x = \frac{24}{20} = \frac{6}{5}\]

\[x = 1\frac{1}{5}.\]