4. Решите уравнение х + \(\frac{3}{7}\) + \(\frac{4}{5}\) = 4\(\frac{2}{5}\).

4. Решим уравнение х + \(\frac{3}{7}\) + \(\frac{4}{5}\) = 4\(\frac{2}{5}\).

1. \(x + \frac{3}{7} + \frac{4}{5} = 4\frac{2}{5}\)
2. \(x + \frac{3}{7} + \frac{4}{5} = \frac{4 \cdot 5 + 2}{5}\)
3. \(x + \frac{3}{7} + \frac{4}{5} = \frac{22}{5}\)
4. \(x = \frac{22}{5} - \frac{3}{7} - \frac{4}{5}\)
5. \(x = \frac{22 \cdot 7}{5 \cdot 7} - \frac{3 \cdot 5}{7 \cdot 5} - \frac{4 \cdot 7}{5 \cdot 7}\)
6. \(x = \frac{154}{35} - \frac{15}{35} - \frac{28}{35}\)
7. \(x = \frac{154 - 15 - 28}{35}\)
8. \(x = \frac{111}{35}\)
9. \(x = 3\frac{6}{35}\)

Ответ: \(x = 3\frac{6}{35}\)