Réponse:
[tex]a) \: \frac{3}{7} \div \frac{4}{5} = \frac{3}{7} \times \frac{5}{4} = \frac{15}{28} \\ b) \: \frac{6}{11} \div \frac{5}{4} = \frac{6}{11} \times \frac{4}{5} = \frac{24}{55} \\ c) \frac{11}{9} \div \frac{1}{2} = \frac{11}{9} \times \frac{2}{1} = \frac{22}{9} \\ d) \frac{15}{4} \div 2 = \frac{15}{4} \times \frac{1}{2} = \frac{15}{8} \\ e)4 \div \frac{7}{9} = 4 \times \frac{9}{7} = \frac{36}{7} \\ f) \frac{3}{8} \div \frac{5}{7} = \frac{3}{8} \times \frac{7}{5} = \frac{21}{40} [/tex]
