Решение:
- а) \(7\frac{1}{8} : 4\frac{3}{8} \cdot 8 = \frac{57}{8} : \frac{35}{8} \cdot 8 = \frac{57}{8} \cdot \frac{8}{35} \cdot 8 = \frac{57}{35} \cdot 8 = \frac{456}{35}\)
- б) \(11\frac{1}{3} : \frac{4}{21} : 4\frac{1}{4} = \frac{34}{3} : \frac{4}{21} : \frac{17}{4} = \frac{34}{3} \cdot \frac{21}{4} \cdot \frac{4}{17} = \frac{34}{1} \cdot \frac{7}{4} \cdot \frac{4}{17} = 2 \cdot 7 \cdot 1 = 14\)
- в) \(1\frac{7}{9} : 2\frac{2}{5} : 1\frac{3}{5} = \frac{16}{9} : \frac{12}{5} : \frac{8}{5} = \frac{16}{9} \cdot \frac{5}{12} \cdot \frac{5}{8} = \frac{16}{12} \cdot \frac{25}{72} = \frac{4}{3} \cdot \frac{25}{72} = \frac{1}{3} \cdot \frac{25}{18} = \frac{25}{54}\)
Ответ: а) \(\frac{456}{35}\); б) 14; в) \(\frac{25}{54}\)