Вычислите:
1) $(-\frac{3}{14} - \frac{8}{21}) : \frac{20}{21}$;
2) $\frac{3}{8} : (-\frac{5}{8}) - (-2\frac{1}{4}) : (-1\frac{4}{11})$;
3) $(-4\frac{1}{12} + 3\frac{9}{10}) : 3\frac{3}{10}$;
4) $(\frac{11}{14} - \frac{5}{6}) : (\frac{11}{14} - \frac{3}{4})$.
$(-\frac{3}{14} - \frac{8}{21}) : \frac{20}{21} = (-\frac{9}{42} - \frac{16}{42}) : \frac{20}{21} = -\frac{25}{42} * \frac{21}{20} = -\frac{5}{2} * \frac{1}{4} = -\frac{5}{8}$
$\frac{3}{8} : (-\frac{5}{8}) - (-2\frac{1}{4}) : (-1\frac{4}{11}) = \frac{3}{8} : (-\frac{5}{8}) - (-\frac{9}{4}) : (-\frac{15}{11}) = \frac{3}{8} * (-\frac{8}{5}) - (-\frac{9}{4}) * (-\frac{11}{15}) = \frac{3}{1} * (-\frac{1}{5}) - (-\frac{3}{4}) * (-\frac{11}{5}) = -\frac{3}{5} - \frac{33}{20} = -\frac{12}{20} - \frac{33}{20} = -\frac{45}{20} = -\frac{9}{4} = -2\frac{1}{4}$
$(-4\frac{1}{12} + 3\frac{9}{10}) : 3\frac{3}{10} = (-3\frac{65}{60} + 3\frac{54}{60}) : \frac{33}{10} = -\frac{11}{60} * \frac{10}{33} = -\frac{1}{6} * \frac{1}{3} = -\frac{1}{18}$
$(\frac{11}{14} - \frac{5}{6}) : (\frac{11}{14} - \frac{3}{4}) = (\frac{33}{42} - \frac{35}{42}) : (\frac{22}{28} - \frac{21}{28}) = -\frac{2}{42} : \frac{1}{28} = -\frac{1}{21} * \frac{28}{1} = -\frac{1}{3} * \frac{4}{1} = -\frac{4}{3} = -1\frac{1}{3}$
Пожауйста, оцените решение
