ГДЗ по алгебре 7 класс Макарычев Задание 634

\[\boxed{\text{634\ (634).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ \frac{x}{4} + \frac{x}{3} = 14\ \ \ | \cdot 12\]

\[3x + 4x = 168\]

\[7x = 168\]

\[x = 24\]

\[Ответ:x = 24.\]

\[\textbf{б)}\ \frac{a}{2} - \frac{a}{8} = 5\ \ \ \ | \cdot 8\]

\[4a - a = 40\]

\[3a = 40\]

\[a = \frac{40}{3}\]

\[a = 13\frac{1}{3}\]

\[Ответ:a = 13\frac{1}{3}.\]

\[\textbf{в)}\ \frac{y}{4} = y - 1\ \ \ \ | \cdot 4\]

\[y = 4 \cdot (y - 1)\]

\[y = 4y - 4\]

\[4y - y = 4\]

\[3y = 4\]

\[y = \frac{4}{3}\]

\[y = 1\frac{1}{3}\]

\[Ответ:y = 1\frac{1}{3}.\]

\[\textbf{г)}\ 2z + 3 = \frac{2z}{5}\ \ \ \ \ \ \ \ \ | \cdot 5\]

\[5 \cdot (2z + 3) = 2z\]

\[10z + 15 = 2z\]

\[10z - 2z = - 15\]

\[8z = - 15\]

\[z = - \frac{15}{8}\]

\[z = - 1\frac{7}{8}\]

\[Ответ:z = - 1\frac{8}{7}.\]

\[\textbf{д)}\ \frac{2c}{3} - \frac{4c}{5} = 7\ \ \ \ | \cdot 15\]

\[5 \cdot 2c - 4c \cdot 3 = 15 \cdot 7\]

\[10c - 12c = 105\]

\[- 2c = 105\]

\[c = - 52,5\]

\[Ответ:c = - 52,5.\]

\[\textbf{е)}\ \frac{5x}{9} + \frac{x}{3} + 4 = 0\ \ \ | \cdot 9\]

\[5x + 3x + 36 = 0\]

\[8x = - 36\]

\[x = - 4,5\]

\[Ответ:x = - 4,5.\]

\[\textbf{ж)}\ \frac{4a}{9} + 1 = \frac{5a}{12}\ \ \ \ \ \ \ \ \ \ \ | \cdot 36\]

\[4 \cdot 4a + 36 = 3 \cdot 5a\]

\[16a - 15a = - 36\]

\[a = - 36\]

\[Ответ:a = - 36.\]

\[\textbf{з)}\ \frac{5m}{12} - \frac{m}{8} = \frac{1}{3}\ \ \ \ \ \ \ \ | \cdot 24\]

\[2 \cdot 5m - 3m = 8\]

\[10m - 3m = 8\]

\[7m = 8\]

\[m = \frac{8}{7}\]

\[m = 1\frac{1}{7}\]

\[Ответ:m = 1\frac{1}{7}.\]

\[\textbf{и)}\ \frac{3n}{14} + \frac{n}{2} = \frac{2}{7}\ \ \ \ \ \ \ \ \ \ | \cdot 14\]

\[3n + 7n = 4\]

\[10n = 4\]

\[n = 0,4\]

\[Ответ:n = 0,4.\]