1) \(8\frac{9}{10} - x = 4\frac{5}{6}\)
\(x = 8\frac{9}{10} - 4\frac{5}{6}\)
\(x = 8\frac{27}{30} - 4\frac{25}{30}\)
\(x = 4\frac{2}{30}\)
\(x = 4\frac{1}{15}\)
2) \(\frac{9}{14} + (x - \frac{3}{7}) = \frac{23}{28}\)
\(x - \frac{3}{7} = \frac{23}{28} - \frac{9}{14}\)
\(x - \frac{3}{7} = \frac{23}{28} - \frac{18}{28}\)
\(x - \frac{3}{7} = \frac{5}{28}\)
\(x = \frac{5}{28} + \frac{3}{7}\)
\(x = \frac{5}{28} + \frac{12}{28}\)
\(x = \frac{17}{28}\)
Ответ: 1) \(4\frac{1}{15}\); 2) \(\frac{17}{28}\)