Реши уравнения: а) 3/7a + 2/5 = 1; ж) m + 3/8m = 1/4; з) y - 2/9y = 4 2/3; и) 2/5z + 2/3z - 7/15z = 2 1/2

Решаю уравнения из твоего задания: а) $\frac{3}{7}a + \frac{2}{5} = 1$ $$\frac{3}{7}a = 1 - \frac{2}{5}$$ $$\frac{3}{7}a = \frac{3}{5}$$ $$a = \frac{3}{5} \cdot \frac{7}{3}$$ $$a = \frac{7}{5}$$ $$a = 1\frac{2}{5}$$ **Ответ: $a = 1\frac{2}{5}$** ж) $m + \frac{3}{8}m = \frac{1}{4}$ $$1m + \frac{3}{8}m = \frac{1}{4}$$ $$\frac{8}{8}m + \frac{3}{8}m = \frac{1}{4}$$ $$\frac{11}{8}m = \frac{1}{4}$$ $$m = \frac{1}{4} : \frac{11}{8}$$ $$m = \frac{1}{4} \cdot \frac{8}{11}$$ $$m = \frac{2}{11}$$ **Ответ: $m = \frac{2}{11}$** з) $y - \frac{2}{9}y = 4\frac{2}{3}$ $$\frac{9}{9}y - \frac{2}{9}y = \frac{14}{3}$$ $$\frac{7}{9}y = \frac{14}{3}$$ $$y = \frac{14}{3} : \frac{7}{9}$$ $$y = \frac{14}{3} \cdot \frac{9}{7}$$ $$y = 6$$ **Ответ: y = 6** и) $\frac{2}{5}z + \frac{2}{3}z - \frac{7}{15}z = 2\frac{1}{2}$ $$\frac{6}{15}z + \frac{10}{15}z - \frac{7}{15}z = \frac{5}{2}$$ $$\frac{9}{15}z = \frac{5}{2}$$ $$\frac{3}{5}z = \frac{5}{2}$$ $$z = \frac{5}{2} : \frac{3}{5}$$ $$z = \frac{5}{2} \cdot \frac{5}{3}$$ $$z = \frac{25}{6}$$ $$z = 4\frac{1}{6}$$ **Ответ: $z = 4\frac{1}{6}$**