в) \frac{4}{9} b + \frac{3}{7} = 1;

в) Решим уравнение:

1. \(\frac{4}{9} b + \frac{3}{7} = 1\)
2. \(\frac{4}{9} b = 1 - \frac{3}{7}\)
3. \(\frac{4}{9} b = \frac{7}{7} - \frac{3}{7}\)
4. \(\frac{4}{9} b = \frac{4}{7}\)
5. \(b = \frac{4}{7} : \frac{4}{9}\)
6. \(b = \frac{4}{7} \cdot \frac{9}{4}\)
7. \(b = \frac{9}{7}\)
8. \(b = 1 \frac{2}{7}\)

Ответ: \(b = 1 \frac{2}{7}\)