20 point!!!!!! aider moi ,a faire l'exercice 88

Salut !

A = (3 - 2/3) / (4/3 * 7)
A = (9/3 - 2/3) / (28/3)
A = (7/3) / (28/3)
A = 7/3 * 3/28
A = 7/28
C = 1/4

B = ((2/3) / (5/6)) - 2/5
B = (2/3 * 6/5) - 2/5
B = 12/15 - 2/5
B = 4/5 - 2/5
B = 2/5

C = (-3/4 + 1/2) / (2/5 - 5/2)
C = (-3/4 + 2/4) / (4/10 - 25/10)
C = (-1/4) / (-21/10)
C = -1/4 * (10/-21)
C = -10/-84 
C = -5/-42 
C = 5/42

J'espère t'avoir aidé(e) ! :)