Réponse :
[tex]\frac{4}{5} - \frac{3}{15} = \frac{12}{15} - \frac{3}{15} = \frac{9}{15} \\\\4 * \frac{5}{8} = \frac{20}{8} = \frac{5}{2} \\\\\frac{7}{2} -\frac{3}{4} * \frac{5}{2} = \frac{7}{2} -\frac{3*5}{4*2} = \frac{7}{2} -\frac{15}{8} = \frac{28}{8} -\frac{15}{8} = \frac{13}{8}[/tex]
