ГДЗ по алгебре 7 класс Макарычев ФГОС Задание 897

\[\boxed{\text{897.}\text{\ }еуроки - ответы\ на\ пятёрку}\]

\[\textbf{а)}\ 2x - \frac{x - 2}{2} = \frac{x}{3} - 6\ \ \ | \cdot 6\]

\[12x - 3 \cdot (x - 2) = 2x - 36\]

\[12x - 3x + 6 - 2x = - 36\]

\[7x = - 36 - 6\]

\[7x = - 42\]

\[x = - 6\]

\[Ответ:x = - 6.\]

\[\textbf{б)}\ 1 + \frac{x + 1}{3} = x - \frac{3x + 1}{8}\ \ \ \ \ | \cdot 24\]

\[24 + 8 \cdot (x + 1) = 24x - 3 \cdot (3x + 1)\]

\[24 + 8x + 8 = 24x - 9x - 3\]

\[8x - 15x = - 3 - 32\]

\[- 7x = - 35\]

\[x = 5\]

\[Ответ:x = 5.\]

\[\textbf{в)}\ \frac{1 - y}{7} + y = \frac{y}{2} + 3\ \ \ \ | \cdot 14\]

\[2 \cdot (1 - y) + 14y = 7y + 42\]

\[2 - 2y + 14y - 7y = 42\]

\[5y = 42 - 2\]

\[5y = 40\]

\[y = 8\]

\[Ответ:y = 8.\]

\[\textbf{г)}\ 6 = \frac{3x - 1}{2} \cdot 2,4\ \ \ \ \ \ \ \ | \cdot 2\]

\[12 = 2,4 \cdot (3x - 1)\]

\[12 = 7,2x - 2,4\]

\[7,2x = 14,4\]

\[x = 14,4\ :7,2 = 144\ :72\]

\[x = 2\]

\[Ответ:x = 2.\]

\[\textbf{д)}\ 0,69 = \frac{5 - 2y}{8} \cdot 13,8\ \ \ \ | \cdot 8\]

\(5,52 = 13,8 \cdot (5 - 2y)\)

\[5,52 = 69 - 27,6y\]

\[27,6y = 69 - 5,52\]

\[27,6y = 63,48\]

\[y = 63,48\ :27,6 = 6348\ :2760\]

\[y = 2,3\]

\[Ответ:y = 2,3.\]

\[\textbf{е)}\ 0,5 \cdot \frac{4 + 2x}{13} = x - 10\ \ \ \ \ \ \ \ \ | \cdot 13\]

\[0,5 \cdot (4 + 2x) = 13 \cdot (x - 10)\]

\[2 + x = 13x - 130\]

\[x - 13x = - 130 - 2\]

\[- 12x = - 132\]

\[x = 11\]

\[Ответ:x = 11.\]