ГДЗ по алгебре 7 класс Макарычев Задание 635

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\[\textbf{а)}\ \frac{6x - 5}{7} = \frac{2x - 1}{3} + 2\ \ \ \ | \cdot 21\]

\[3 \cdot (6x - 5) - 7 \cdot (2x - 1) = 42\]

\[18x - 15 - 14x + 7 = 42\]

\[4x = 42 + 8\]

\[4x = 50\]

\[x = 12,5\]

\[Ответ:x = 12,5.\]

\[\textbf{б)}\ \frac{5 - x}{2} + \frac{3x - 1}{5} = 4\ \ \ \ | \cdot 10\]

\[5 \cdot (5 - x) + 2 \cdot (3x - 1) = 40\]

\[25 - 5x + 6x - 2 = 40\]

\[x = 40 - 23\]

\[x = 17\]

\[Ответ:x = 17.\]

\[\textbf{в)}\ \frac{5x - 7}{12} - \frac{x - 5}{8} = 5\ \ \ \ | \cdot 24\]

\[2 \cdot (5x - 7) - 3 \cdot (x - 5) = 120\]

\[10x - 14 - 3x + 15 = 120\]

\[7x = 120 - 1\]

\[7x = 119\]

\[x = 17\]

\[Ответ:x = 17.\]

\[\textbf{г)}\ \frac{4y - 11}{15} + \frac{13 - 7y}{20} = 2\ \ \ \ | \cdot 60\]

\[4 \cdot (4y - 11) + 3 \cdot (13 - 7y) =\]

\[= 120\]

\[16y - 44 + 39 - 21y = 120\]

\[- 5y = 120 + 5\]

\[- 5y = 125\]

\[y = - 25\]

\[Ответ:y = - 25.\]

\[\textbf{д)}\ \frac{5 - 6y}{3} + \frac{y}{8} = 0\ \ \ \ | \cdot 24\]

\[8 \cdot (5 - 6y) + 3y = 0\]

\[40 - 48y + 3y = 0\]

\[- 45y = - 40\]

\[y = \frac{40}{45}\]

\[y = \frac{8}{9}\]

\[Ответ:y = \frac{8}{9}.\]

\[\textbf{е)}\ \frac{y}{4} - \frac{3 - 2y}{5} = 0\ \ \ \ \ | \cdot 20\]

\[5y - 4 \cdot (3 - 2y) = 0\]

\[5y - 12 + 8y = 0\]

\[13y = 12\]

\[y = \frac{12}{13}\]

\[Ответ:y = \frac{12}{13}.\]