1 Вариант: Вычислите:

а) \(\frac{5}{9} : \frac{2}{7} = \frac{5}{9} \cdot \frac{7}{2} = \frac{5 \cdot 7}{9 \cdot 2} = \frac{35}{18} = 1\frac{17}{18}\) б) \(\frac{7}{18} : \frac{14}{27} = \frac{7}{18} \cdot \frac{27}{14} = \frac{7 \cdot 27}{18 \cdot 14} = \frac{7 \cdot 9 \cdot 3}{9 \cdot 2 \cdot 7 \cdot 2} = \frac{3}{2 \cdot 2} = \frac{3}{4}\) в) \(\frac{3}{7} : 21 = \frac{3}{7} : \frac{21}{1} = \frac{3}{7} \cdot \frac{1}{21} = \frac{3 \cdot 1}{7 \cdot 21} = \frac{3}{7 \cdot 3 \cdot 7} = \frac{1}{7 \cdot 7} = \frac{1}{49}\) г) \(15 : \frac{3}{5} = \frac{15}{1} : \frac{3}{5} = \frac{15}{1} \cdot \frac{5}{3} = \frac{15 \cdot 5}{1 \cdot 3} = \frac{3 \cdot 5 \cdot 5}{3} = 5 \cdot 5 = 25\)