Réponse:

Bon soirée !! voici les réponses

bonsoir:

a:

8/12 = 2/3

40/72 = 5/9

15/35 = 3/7

b:

A = 8/12 + 5/3

A = 2/3 + 5/3

A = 7/3

B = 40/72 - 1/9

B = 5/9 - 1/9

B = 4/9

C = 15/35 + 2/7

C = 3/7 + 2/7

C = 5/7

bonne soirée :)