Bonjour
A = 3 - 2/3 / 4/3 x 7
= 3 - 2/3 x 3/4 x 7
= 3 - (2 x 3 x 7)/(3 x 2 x 2)
= 3 - 7/2
= (3 x 2)/(1 x 2) - 7/2
= 6/2 - 7/2
= -1/2
B = 5/3 - 4/3 x 11/7
= 5/3 - (4 x 11)/(3 x 7)
= 5/3 - 44/21
= (5 x 7)/(3 x 7) - 44/21
= 35/21 - 44/21
= -9/21
= -3/7
Voilà j'espère avoir pu t'aider ^^