calculer et donner le résultat sous forme de fraction irreductible: A=3sur4 - 2sur3 ÷ 8sur15 B=6sur5 - 17sur14 ÷ 5sur7 C=5sur7 + 1sur7 × 4sur3 D=7sur15 - 4sur15

Bonjour

Calculer et donner le résultat sous forme de fraction irréductible :

A = 3/4 - 2/3 : 8/15

A = 3/4 - 2/3 x 15/8

A = 3/4 - 30/24

A = 3/4 - (6 x 5) / (6 x 4)

A = 3/4 - 5/4

A = - 2/4

A = (2 x - 1) / (2 x 2)

A = - 1/2

B = 6/5 - 17/14 : 5/7

B = 6/5 - 17/14 x 7/5

B = (6 x 14) / (5 x 14) - 119/70

B = 84/70 - 119/70

B = - 35/70

B = (35 x - 1) / (35 x 2)

B = - 1/2

C = 5/7 + 1/7 x 4/3

C = 5/7 + 4/21

C = (5 x 3) / (7 x 3) + 4/21

C = 15/24 + 4/21

C = 19/21

D = 7/15 - 4/15 x 5/8

D = 7/15 - 20/120

D = (7 x 2) / (15 x 2) - (4 x 5) / (4 x 30)

D = 14/30 - 5/30

D = 9/30

D = (3 x 3) / (3 x 10)

D = 3/10.