Calculer ex 29 page 21 3ème svp j’en ai besoin pour dm

Bonsoir,

A = 2/7 + 3/5 x 7/3

A = 2/7 + 21/15

A = 2/7 + (3 x 7) / (3 x 5)

A = 2/7 + 7/5

A = (2 x 5) / (7 x 5) + (7 x 7) / (5 x 7)

A = 10/35 + 49/35

A = 59/35

B = (2/7 + 3/5) x 7/3

B = [(2 x 5) / (7 x 5) + (3 x 7) / (5 x 7)] x 7/3

B = (10/35 + 21/35) x 7/3

B = 31/35 x 7/3

B = 217/105

B = (7 x 31) / (7 x 15)

B = 31/15

C = 2/7 x 3/5 x 7/3

C = 6/35 x 7/3

C = 42/105

C = (21 x 2) / (21 x 5)

C = 2/5

D = 2/7 - 3/5 : 7/3

D = 2/7 - 3/5 x 3/7

D = (2 x 5) / (7 x 5) - 9/35

D = 10/35 - 9/35

D = 1/35.