Réponse :
[tex]\frac{a+b}{c} = \frac{\frac{-3}{4}+\frac{-2}{3} }{\frac{2}{5} } = -\frac{85}{24}[/tex]
[tex]\frac{c-a}{b} = \frac{\frac{2}{5}- \frac{-3}{4} }{\frac{-2}{3} } = \frac{-69}{40}[/tex]
[tex]\frac{a*b}{c} = \frac{\frac{-3}{4}*\frac{-2}{3} }{\frac{2}{5} } = \frac{5}{4}[/tex]