a) \frac{7}{9} : \frac{7}{18} = \frac{7}{9} \cdot \frac{18}{7} = \frac{7 \cdot 18}{9 \cdot 7} = \frac{18}{9} = 2
б) \frac{1}{4} : \frac{1}{3} = \frac{1}{4} \cdot \frac{3}{1} = \frac{1 \cdot 3}{4 \cdot 1} = \frac{3}{4}
в) \frac{3}{4} : \frac{7}{9} = \frac{3}{4} \cdot \frac{9}{7} = \frac{3 \cdot 9}{4 \cdot 7} = \frac{27}{28}
г) \frac{3}{7} : \frac{1}{14} = \frac{3}{7} \cdot \frac{14}{1} = \frac{3 \cdot 14}{7 \cdot 1} = \frac{42}{7} = 6
д) \frac{6}{11} : 6 = \frac{6}{11} \cdot \frac{1}{6} = \frac{6 \cdot 1}{11 \cdot 6} = \frac{1}{11}
е) \frac{9}{13} : 3 = \frac{9}{13} \cdot \frac{1}{3} = \frac{9 \cdot 1}{13 \cdot 3} = \frac{9}{39} = \frac{3}{13}
ж) \frac{5}{7} : \frac{1}{7} = \frac{5}{7} \cdot \frac{7}{1} = \frac{5 \cdot 7}{7 \cdot 1} = \frac{35}{7} = 5
з) \frac{15}{22} : 5 = \frac{15}{22} \cdot \frac{1}{5} = \frac{15 \cdot 1}{22 \cdot 5} = \frac{15}{110} = \frac{3}{22}
Ответ: a) 2; б) \frac{3}{4}; в) \frac{27}{28}; г) 6; д) \frac{1}{11}; е) \frac{3}{13}; ж) 5; з) \frac{3}{22}