138. Выполните деление: $$\frac{14}{39} : \frac{21}{52} ; 6) 4 \frac{1}{11} : 2 \frac{19}{22} ; в) 18 : \frac{9}{14}$$

138. Выполните деление:

1. а)
   $$\frac{14}{39} : \frac{21}{52} = \frac{14}{39} \times \frac{52}{21} = \frac{2 \times 7}{3 \times 13} \times \frac{4 \times 13}{3 \times 7} = \frac{2 \times 4}{3 \times 3} = \frac{8}{9}$$
2. б)
   $$4 \frac{1}{11} : 2 \frac{19}{22} = \frac{45}{11} : \frac{61}{22} = \frac{45}{11} \times \frac{22}{61} = \frac{45 \times 2}{61} = \frac{90}{61}$$
3. в)
   $$18 : \frac{9}{14} = 18 \times \frac{14}{9} = 2 \times 14 = 28$$

Ответ: а) $$\frac{8}{9}$$; б) $$\frac{90}{61}$$; в) 28.