Bonjour,
A = [tex] \frac{2}{5} [/tex] × [tex] \frac{7}{4} = \frac{14}{20} = \frac{7}{10} [/tex]
B = [tex] \frac{5}{2} [/tex] × [tex] \frac{3}{10} = \frac{15}{20} = \frac{3}{4} [/tex]
C = [tex] \frac{19}{4} [/tex] × [tex] \frac{6}{5} = \frac{114}{20} = \frac{57}{10} [/tex]
J'espère t'avoir aidé.