Проверочная работа. 1. Вычислите: a) \(\frac{7}{9} \div \frac{5}{3}\); б) \(\frac{8}{15}\); в) \(\frac{15}{28}\); г) \(\frac{35}{16} \div 7\); д) \(x \div \frac{21}{45} = \frac{5}{14}\)?

a) \(\frac{7}{9} \div \frac{5}{3} = \frac{7}{9} \cdot \frac{3}{5} = \frac{7 \cdot 3}{9 \cdot 5} = \frac{21}{45} = \frac{7}{15}\) б) нет задания. в) нет задания. г) \(\frac{35}{16} \div 7 = \frac{35}{16} \div \frac{7}{1} = \frac{35}{16} \cdot \frac{1}{7} = \frac{35 \cdot 1}{16 \cdot 7} = \frac{5}{16}\) д) \(x \div \frac{21}{45} = \frac{5}{14}\) \(x = \frac{5}{14} \cdot \frac{21}{45}\) \(x = \frac{5 \cdot 21}{14 \cdot 45}\) \(x = \frac{105}{630}\) \(x = \frac{1}{6}\)