1. Выполните действия: a) $$1\frac{5}{7} : 1\frac{1}{7}$$; б) $$3\frac{1}{5} : 2\frac{2}{15}$$; в) $$5\frac{2}{3} : 1\frac{1}{12} - 1\frac{7}{12} \cdot 6$$

a) $$1\frac{5}{7} : 1\frac{1}{7} = \frac{12}{7} : \frac{8}{7} = \frac{12}{7} \cdot \frac{7}{8} = \frac{12}{8} = \frac{3}{2} = 1\frac{1}{2}$$ б) $$3\frac{1}{5} : 2\frac{2}{15} = \frac{16}{5} : \frac{32}{15} = \frac{16}{5} \cdot \frac{15}{32} = \frac{16 \cdot 15}{5 \cdot 32} = \frac{1 \cdot 3}{1 \cdot 2} = \frac{3}{2} = 1\frac{1}{2}$$ в) $$5\frac{2}{3} : 1\frac{1}{12} - 1\frac{7}{12} \cdot 6 = \frac{17}{3} : \frac{13}{12} - \frac{19}{12} \cdot 6 = \frac{17}{3} \cdot \frac{12}{13} - \frac{19 \cdot 6}{12} = \frac{17 \cdot 4}{13} - \frac{19}{2} = \frac{68}{13} - \frac{19}{2} = \frac{68 \cdot 2 - 19 \cdot 13}{26} = \frac{136 - 247}{26} = \frac{-111}{26} = -4\frac{7}{26}$$ Ответ: a) $$1\frac{1}{2}$$ б) $$1\frac{1}{2}$$ в) $$-4\frac{7}{26}$$