j'ai besoin svp j'arrive pas à trouver c trop dur​

Bonsoir

A = 7/3 - 4/3 : 8/5

A = 7/3 - 4/3 x 5/8

A = (7 x 8) / (5 x 8) - 20/24

A = 56/24 - 20/24

A = 36/24

A = (12 x 3) / (12 x 2)

A = 3/2

B = - 4/9 x 1/5 : 3/7

B = - 4/45 x 7/3

B = - 28/135

C = - 8/3 : - 5/6 + 7/4

C = - 8/3 x - 6/5 + 7/4

C = 48/15 + 7/4

C = (48 x 4) / (15 x 4) + (7 x 15) / (4 x 15)

C = 192/60 + 105/60

C = 297/60

C = (3 x 99) / (3 x 20)

C = 99/20