aidez moi encore svp ;)

Réponse :

A = 3/7 - 2/5 * 15/4

A = 3/7 - (2/5 * 3/2 * 5/2)

A = 3/7 - (3/2)

A = 6/14 - 21/14

A = -27/14

B= 1/8 - 7/12 / 7/6 + 7/12

B = 1/8 - (7/12 * 6/7) + 7/12

B =  1/8 - (1/2) + 7/12

B = 3/24 - 12/24 + 14/24

B = 5/24

C = (5/3 - 7/9) / (1/4 - 1/2)

C =  (15/9 - 7/9) / (1/4 - 2/4)

C =  (8/9) / (- 1/4)

C = - 32/9

Explications étape par étape