339. Решите уравнение: 1) x + \(\frac{7}{8}\) = 5; 2) x - 5 \(\frac{8}{21}\) = 1 \(\frac{17}{42}\); 3) 9 \(\frac{1}{45}\) - x = 3 \(\frac{1}{30}\).

1) \(x + \frac{7}{8} = 5\)

\(x = 5 - \frac{7}{8}\)

\(x = \frac{5 \cdot 8}{8} - \frac{7}{8}\)

\(x = \frac{40}{8} - \frac{7}{8}\)

\(x = \frac{40 - 7}{8}\)

\(x = \frac{33}{8}\)

\(x = 4 \frac{1}{8}\)

Ответ: \(4 \frac{1}{8}\)

2) \(x - 5 \frac{8}{21} = 1 \frac{17}{42}\)

\(x = 1 \frac{17}{42} + 5 \frac{8}{21}\)

\(x = \frac{1 \cdot 42 + 17}{42} + \frac{5 \cdot 21 + 8}{21}\)

\(x = \frac{59}{42} + \frac{113}{21}\)

\(x = \frac{59}{42} + \frac{113 \cdot 2}{21 \cdot 2}\)

\(x = \frac{59}{42} + \frac{226}{42}\)

\(x = \frac{59 + 226}{42}\)

\(x = \frac{285}{42}\)

\(x = \frac{95}{14}\)

\(x = 6 \frac{11}{14}\)

Ответ: \(6 \frac{11}{14}\)

3) \(9 \frac{1}{45} - x = 3 \frac{1}{30}\)

\(x = 9 \frac{1}{45} - 3 \frac{1}{30}\)

\(x = \frac{9 \cdot 45 + 1}{45} - \frac{3 \cdot 30 + 1}{30}\)

\(x = \frac{406}{45} - \frac{91}{30}\)

\(x = \frac{406 \cdot 2}{45 \cdot 2} - \frac{91 \cdot 3}{30 \cdot 3}\)

\(x = \frac{812}{90} - \frac{273}{90}\)

\(x = \frac{812 - 273}{90}\)

\(x = \frac{539}{90}\)

\(x = 5 \frac{89}{90}\)

Ответ: \(5 \frac{89}{90}\)