Решим уравнения:
а) 3,45 * (2,08 - y) = 6,21
- 2,08 - y = 6,21 / 3,45
- 2,08 - y = 1,8
- y = 2,08 - 1,8
- y = 0,28
б) $$y + 4\frac{7}{10} = 5\frac{8}{15}$$
- $$y = 5\frac{8}{15} - 4\frac{7}{10}$$
- $$y = 5\frac{16}{30} - 4\frac{21}{30}$$
- $$y = 4\frac{46}{30} - 4\frac{21}{30}$$
- $$y = \frac{25}{30}$$
- $$y = \frac{5}{6}$$
в) y : 7 = $$5\frac{9}{28}$$
- $$y = 5\frac{9}{28} \cdot 7$$
- $$y = \frac{149}{28} \cdot 7$$
- $$y = \frac{149}{4}$$
- $$y = 37\frac{1}{4}$$
- $$y = 37,25$$
Ответ: a) y = 0,28; б) $$y = \frac{5}{6}$$; в) y = 37,25