Bonjour pouvez-vous m’aider s’il vous plaît merci d’avance

Bonjour

A = 1/3 + 2 (5/7 - 1)

A = 1/3 + 10/7 - 2

A = (1 x 7) / (3 x 7) + (10 x 3) / (7 x 3) - (2 x 21) / (1 x 21)

A = 7/21 + 30/21 - 42/21

A = - 5/21

B = (1 - 1/3) : (1 + 1/3)

B = [(1 x 3) / (1 x 3) - 1/3)] : [(1 x 3) / (1 x 3) + 1/3]

B = (3/3 - 1/3) : (3/3 + 1/3)

B = 2/3 : 4/3

B = 2/3 x 3/4

B = 6/12

B = (6 x 1) / (6 x 2)

B = 1/2

C = - 2 (1/3 : 5 + 1)

C = - 2 (1/3 x 1/5 + 1)

C = - 2 (1/15 + 1)

C = - 2/15 - 2

C = - 2/15 - (2 x 15) / (1 x 15)

C = - 2/15 - 30/15

C = - 32/15

D = (5 + 7/2) : 5

D = [(5 x 2) / (1 x 2) + 7/2] : 5

D = (10/2 + 7/2) : 5

D = 17/2 : 5

D = 17/2 x 1/5

D = 17/10.