3 Решите уравнение: a) \(x + \frac{7}{20} = \frac{4}{5}\);

a) \(x + \frac{7}{20} = \frac{4}{5}\)

\(x = \frac{4}{5} - \frac{7}{20}\)

\(x = \frac{4 \cdot 4}{5 \cdot 4} - \frac{7}{20}\)

\(x = \frac{16}{20} - \frac{7}{20}\)

\(x = \frac{16-7}{20}\)

\(x = \frac{9}{20}\)

Ответ: \(x = \frac{9}{20}\)