ГДЗ по алгебре 7 класс Макарычев Задание 630

\[\boxed{\text{630\ (630).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ 5x + 3 \cdot (x - 1) = 6x + 11\]

\[5x + 3x - 3 - 6x = 11\]

\[2x = 11 + 3\]

\[2x = 14\]

\[x = 7\]

\[Ответ:x = 7.\]

\[\textbf{б)}\ 3x - 5 \cdot (2 - x) = 54\]

\[3x - 10 + 5x = 54\]

\[8x = 54 + 10\]

\[8x = 64\]

\[x = 8\]

\[Ответ:x = 8.\]

\[\textbf{в)}\ 8 \cdot (y - 7) - 3 \cdot (2y + 9) = 15\]

\[8y - 56 - 6y - 27 = 15\]

\[2y = 15 + 83\]

\[2y = 98\]

\[y = 49\]

\[Ответ:y = 49.\]

\[\textbf{г)}\ 0,6 - 0,5 \cdot (y - 1) = y + 0,5\]

\[0,6 - 0,5y + 0,5 - y = 0,5\]

\[- 1,5y = 0,5 - 1,1\]

\[- 1,5y = - 0,6\]

\[y = - 0,6\ :( - 1,5) = 6\ :15\]

\[y = 0,4\]

\[Ответ:y = 0,4.\]

\[\textbf{д)}\ 6 + (2 - 4x) + 5 =\]

\[= 3 \cdot (1 - 3x)\]

\[6 + 2 - 4x + 5 = 3 - 9x\]

\[9x - 4x = 3 - 13\]

\[5x = - 10\]

\[x = - 2\]

\[Ответ:x = - 2.\]

\[y - 0,5 - 0,5 + 0,2y + 1 = 0\]

\[1,2y = 0\]

\[y = 0\]

\[Ответ:y = 0.\]

\(ж)\ 0,15 \cdot (x - 4) =\)

\(= 9,9 - 0,3 \cdot (x - 1)\)

\[0,15x - 0,6 = 9,9 - 0,3x + 0,3\]

\[0,15x + 0,3x = 10,2 + 0,6\]

\[0,45x = 10,8\]

\[x = 10,8\ :0,45 = 1080\ :45\]

\[x = 24\]

\[Ответ:x = 24.\]

\[\textbf{з)}\ 3 \cdot (3x - 1) + 2 =\]

\[= 5 \cdot (1 - 2x) - 1\]

\[9x - 3 + 2 = 5 - 10x - 1\]

\[9x + 10x = 4 + 1\]

\[19x = 5\ \]

\[x = \frac{5}{19}\]

\[Ответ:x = \frac{5}{19}.\]