[tex]a) \frac{12}{35} : \frac{18}{14} = \frac{12}{35} \times \frac{14}{18} = \frac{12 \times 14}{35 \times 18} = \frac{168}{630} = \frac{4}{15} \\ \\ b)20 : \frac{15}{7} = 20 \times \frac{7}{15} = \frac{140}{15} = \frac{28}{3} \\ \\ c)28 : \frac{8}{5} = 28 \times \frac{5}{8} = \frac{140}{8} = \frac{35}{2} \\ \\ d) \frac{21}{15} : 14 = \frac{7}{5} : 14 = \frac{7}{5} \times \frac{1}{14} = \frac{7 \times 1}{5 \times 14} = \frac{7}{70} = \frac{1}{10} \\ \\ e) \frac{25}{9} : \frac{5}{6} = \frac{25}{9} \times \frac{6}{5} = \frac{25 \times 6}{9 \times 5} = \frac{150}{45} = \frac{10}{3} [/tex]
