3. Выполните действия: 37 a) -:- 79 г) 56:- 8 5 15 б) -:- 28 42 3 13 д) 2-:-20 5 69 в) -:- 13 52 33 e) 3-:4-. 48 7

a) $$\frac{3}{7} : \frac{7}{9} = \frac{3}{7} \cdot \frac{9}{7} = \frac{3 \cdot 9}{7 \cdot 7} = \frac{27}{49}$$

б) $$\frac{5}{28} : \frac{15}{42} = \frac{5}{28} \cdot \frac{42}{15} = \frac{5 \cdot 42}{28 \cdot 15} = \frac{1 \cdot 6}{4 \cdot 3} = \frac{6}{12} = \frac{1}{2}$$

в) $$\frac{6}{13} : \frac{9}{52} = \frac{6}{13} \cdot \frac{52}{9} = \frac{6 \cdot 52}{13 \cdot 9} = \frac{2 \cdot 4}{1 \cdot 3} = \frac{8}{3} = 2\frac{2}{3}$$

г) $$56 : \frac{7}{8} = 56 \cdot \frac{8}{7} = \frac{56 \cdot 8}{7} = \frac{8 \cdot 8}{1} = 64$$

д) $$2\frac{3}{5} : \frac{13}{20} = \frac{2 \cdot 5 + 3}{5} : \frac{13}{20} = \frac{13}{5} : \frac{13}{20} = \frac{13}{5} \cdot \frac{20}{13} = \frac{13 \cdot 20}{5 \cdot 13} = \frac{20}{5} = 4$$

e) $$3\frac{3}{4} : 4\frac{3}{8} = \frac{3 \cdot 4 + 3}{4} : \frac{4 \cdot 8 + 3}{8} = \frac{15}{4} : \frac{35}{8} = \frac{15}{4} \cdot \frac{8}{35} = \frac{15 \cdot 8}{4 \cdot 35} = \frac{3 \cdot 2}{1 \cdot 7} = \frac{6}{7}$$

Ответ: a) $$\frac{27}{49}$$, б) $$\frac{1}{2}$$, в) $$2\frac{2}{3}$$, г) $$64$$, д) $$4$$, e) $$\frac{6}{7}$$