Réponse:
[tex]a = \frac{3}{7} + \frac{1}{2} = \frac{6 + 7}{14} = \frac{13}{14} [/tex]
[tex]b = \frac{2}{9} + \frac{15}{8} = \frac{16 + 135}{72} = \frac{151}{72} [/tex]
[tex]c = \frac{9}{5} - \frac{12}{17} = \frac{153 - 60}{85} = \frac{93}{85} [/tex]
[tex]d = \frac{8}{7} - \frac{1}{6} = \frac{48 - 7}{42} = \frac{41}{42} [/tex]
