a) 3/4 : (-1/2); -2/3 * 4/9; -3/5 : (9/5); б) -3/8 : 1/16; -2/3 : (-1/9); 3/7 : (9/14); в) 3/5 : (-2/15); -8/9 * 4/5; -9/10 : (-9/20); г) -2/5 : 3/10; 3/8 : (-1/4); -5/6 : (-7/18); д) 2/3 : (-1/6); -3/5 : (-1/15); -3/20 : 9/10; е) -3/7 : (-9/28); -16/25 * 8/15; 5/9 : (-5/18)

Решение:

• a)
• \(\frac{3}{4} : \left(-\frac{1}{2}\right) = \frac{3}{4} \cdot (-2) = -\frac{3 \cdot 2}{4} = -\frac{3}{2} = -1\frac{1}{2}\)
• \(-\frac{2}{3} \cdot \frac{4}{9} = -\frac{2 \cdot 4}{3 \cdot 9} = -\frac{8}{27}\)
• \(-\frac{3}{5} : \frac{9}{5} = -\frac{3}{5} \cdot \frac{5}{9} = -\frac{3 \cdot 5}{5 \cdot 9} = -\frac{1}{3}\)

• б)
• \(-\frac{3}{8} : \frac{1}{16} = -\frac{3}{8} \cdot 16 = -\frac{3 \cdot 16}{8} = -6\)
• \(-\frac{2}{3} : \left(-\frac{1}{9}\right) = -\frac{2}{3} \cdot (-9) = \frac{2 \cdot 9}{3} = 6\)
• \(\frac{3}{7} : \left(-\frac{9}{14}\right) = \frac{3}{7} \cdot \left(-\frac{14}{9}\right) = -\frac{3 \cdot 14}{7 \cdot 9} = -\frac{2}{3}\)

• в)
• \(\frac{3}{5} : \left(-\frac{2}{15}\right) = \frac{3}{5} \cdot \left(-\frac{15}{2}\right) = -\frac{3 \cdot 15}{5 \cdot 2} = -\frac{9}{2} = -4\frac{1}{2}\)
• \(-\frac{8}{9} \cdot \frac{4}{5} = -\frac{8 \cdot 4}{9 \cdot 5} = -\frac{32}{45}\)
• \(-\frac{9}{10} : \left(-\frac{9}{20}\right) = -\frac{9}{10} \cdot \left(-\frac{20}{9}\right) = \frac{9 \cdot 20}{10 \cdot 9} = 2\)

• г)
• \(-\frac{2}{5} : \frac{3}{10} = -\frac{2}{5} \cdot \frac{10}{3} = -\frac{2 \cdot 10}{5 \cdot 3} = -\frac{4}{3} = -1\frac{1}{3}\)
• \(\frac{3}{8} : \left(-\frac{1}{4}\right) = \frac{3}{8} \cdot (-4) = -\frac{3 \cdot 4}{8} = -\frac{3}{2} = -1\frac{1}{2}\)
• \(-\frac{5}{6} : \left(-\frac{7}{18}\right) = -\frac{5}{6} \cdot \left(-\frac{18}{7}\right) = \frac{5 \cdot 18}{6 \cdot 7} = \frac{15}{7} = 2\frac{1}{7}\)

• д)
• \(\frac{2}{3} : \left(-\frac{1}{6}\right) = \frac{2}{3} \cdot (-6) = -\frac{2 \cdot 6}{3} = -4\)
• \(-\frac{3}{5} : \left(-\frac{1}{15}\right) = -\frac{3}{5} \cdot (-15) = \frac{3 \cdot 15}{5} = 9\)
• \(-\frac{3}{20} : \frac{9}{10} = -\frac{3}{20} \cdot \frac{10}{9} = -\frac{3 \cdot 10}{20 \cdot 9} = -\frac{1}{6}\)

• е)
• \(-\frac{3}{7} : \left(-\frac{9}{28}\right) = -\frac{3}{7} \cdot \left(-\frac{28}{9}\right) = \frac{3 \cdot 28}{7 \cdot 9} = \frac{4}{3} = 1\frac{1}{3}\)
• \(-\frac{16}{25} \cdot \frac{8}{15} = -\frac{16 \cdot 8}{25 \cdot 15} = -\frac{128}{375}\)
• \(\frac{5}{9} : \left(-\frac{5}{18}\right) = \frac{5}{9} \cdot \left(-\frac{18}{5}\right) = -\frac{5 \cdot 18}{9 \cdot 5} = -2\)