bonjour, jai cette question dans mes exos de maths et je n'ai pas vraiment compris. pouvez vous m'aidez ?​

Bonjour

A = 2/5 - 7/15

A = (2 x 3) / (5 x 3) - 7/15

A = 6/15 - 7/15

A = - 1/15

B = 3 + 1/8

B = (3 x 8) / (1 x 8) + 1/8

B = 24/8 + 1/8

B = 25/8

C = - 5/7 x 3/10

C = - 15/70

C = (5 x - 3) / (5 x 14)

C = - 3/14

D = 1/5 + 1/5 (4/12 + 3/9)

D = 1/5 + 1/5 [(4 x 3) / (12 x 3) + (3 x 4) / (9 x 4)]

D = 1/5 + 1/5 (12/36 + 12/36)

D = 1/5 + 1/5 (24/36)

D = 1/5 + 1/5 [(12 x 2) / (12 x 3)]

D = 1/5 + 1/5 (2/3)

D = (1 x 3) / (5 x 3) + 2/15

D = 3/15 + 2/15

D = 5/15

D = (5 x 1) / (5 x 3)

D = 1/3.