Bonsoir je suis en 4ème pouvez vous m aider a faire l exercice 43 merci d avance

Bonsoir,

A = 5/7 - (3/2 - 5/4)
A = 5/7 - [(3 x 2) / (2 x 2) - 5/4]
A = 5/7 - (6/4 - 5/4)
A = 5/7 - 1/4
A = (5 x 4) / (7 x 4) - (1 x 7) / (4 x 7)
A = 20/28 - 7/28
A = 13/28

B = (5/8 + - 7/4) - (- 1/3 - 4/3)
B = [5/8 - (7 x 2) / (4 x 2)] - (- 5/3)
B = (5/8 - 14/8) + 5/3
B = - 9/8 + 5/3
B = (- 9 x 3) / (8 x 3) + (5 x 8) / (3 x 8)
B = - 27/24 + 40/24
B = 13/24

A= 5/7 - (3/2 - 5/4)
A= 5/7 - (6/4 - 5/4)
A= 5/7 - 1/4
A= 20/28 - 7/28
A= 13/28

B= (5/8 + -7/4) - (-1/3 - 4/3)
B= (5/8 + -14/8) - -5/3
B= -9/8 - -5/3
B= -27/24 - -40/24
B= 13/24