Réponse :

Explications étape par étape

Bonjour

A = 6/7 - 4/7 x 5/2

A = 6/7 - (4 x 5)/(7 x 2)

A = 6/7 - 20/14

A = (6 x 2)/(7 x 2) - 20/14

A = 12/14 - 20/14

A = -8/14

A = (-2 x 4)/(2 x 7)

A = -4/7

B = 2/3 - 3/2 x 4/9 + 1/2

B = 2/3 - 3/9 x 4/2 + 1/2

B = 2/3 - 3/(3 x 3) x (2 x 2)/2 + 1/2

B = 2/3 - 1/3 x 2 + 1/2

B = 2/3 - 2/3 + 1/2

B = 1/2

C = 2/5 / (3 - 7/10)

C = 2/5 / [(3 x 10)/10 - 7/10]

C = 2/5 / (30/10 - 7/10)

C = 2/5 / (23/10)

C = 2/5 x 10/23

C = 2/23 x 10/5

C = 2/23 x 2

C = 4/23