4.309 Найдите частное: a) \frac{7}{9}:\frac{2}{3}; B) \frac{16}{35}:(-\frac{4}{25}); г) -\frac{5}{8}:(-\frac{15}{64}); д) \frac{4}{5}:(-16);

a) \[\frac{7}{9}:\frac{2}{3} = \frac{7}{9} \cdot \frac{3}{2} = \frac{7 \cdot 3}{9 \cdot 2} = \frac{7 \cdot 1}{3 \cdot 2} = \frac{7}{6} = 1\frac{1}{6}\]

в) \[\frac{16}{35}:(-\frac{4}{25}) = \frac{16}{35} \cdot (-\frac{25}{4}) = -\frac{16 \cdot 25}{35 \cdot 4} = -\frac{4 \cdot 5}{7 \cdot 1} = -\frac{20}{7} = -2\frac{6}{7}\]

г) \[-\frac{5}{8}:(-\frac{15}{64}) = -\frac{5}{8} \cdot (-\frac{64}{15}) = \frac{5 \cdot 64}{8 \cdot 15} = \frac{1 \cdot 8}{1 \cdot 3} = \frac{8}{3} = 2\frac{2}{3}\]

д) \[\frac{4}{5}:(-16) = \frac{4}{5} \cdot (-\frac{1}{16}) = -\frac{4}{5 \cdot 16} = -\frac{1}{5 \cdot 4} = -\frac{1}{20}\]