Vous pouvez m’aider pour l’exercice 1sil vous plaît..

Bonjour,

A = (3/7 - 8/21) x (7/12 - 3/18)

A = [(3 x 3) / (7 x 3) - 8/21] x [(7 x 3) / (12 x 3) - (3 x 2) / (18 x 2)]

A = (9/21 - 8/21) x (21/36 - 6/36)

A = 1/21 x 15/36

A = 15/756

A = (3 x 5) / (3 x 252)

A = 5/252

B = 3/5 - 7/5 : 4/9 x 15

B = 3/5 - 7/5 x 9/4 x 15

B = 3/5 - 63/20 x 15

B = 3/5 - 945/20

B = (3 x 4) / (5 x 4) - 945/20

B = 12/20 - 945/20

B = - 933/20

C = - 2/5 + 5/2 x 8/25 : 7/10

C = - 2/5 + 40/50 x 10/7

C = - 2/5 + 400/350

C = (- 2 x 70) / (5 x 70) + 400/350

C = - 140/350 + 400/350

C = 260/350

C = (10 x 26) / (10 x 35)

C = 26/35.