Merci de m’aidez pour l’exercice 69

Bonjour,

a. (3 - 2/3) / (4/3 x 7)

= [(3 x 3) / (1 x 3) - 2/3] : 28/3

= (9/3 - 2/3) : 28/3

= 7/3 x 3/28

= 21/84

= (21 x 1) / (21 x 4)

= 1/4

b. 2/3 : 5/6 - 2/5

= 2/3 x 6/5 - 2/5

= 12/15 - 2/5

= 12/15 - (2 x 3) / (5 x 3)

= 12/15 - 6/15

= 6/15

= (3 x 2) / (3 x 5)

= 2/5

c. (- 3/4 + 1/2) : (2/5 - 5/2)

= [- 3/4 + (1 x 2) / (2 x 2)] : [(2 x 2) / (5 x 2) - (5 x 5) / (2 x 5)]

= (- 3/4 + 2/4) : (4/10 - 25/10)

= - 1/4 : - 21/10

= - 1/4 x - 10/21

= 10/84

= (2 x 5) / (2 x 42)

= 5/42.

Réponse :

Bonjour

Explications étape par étape

(3 - 2/3)/(4/3 x 7)

= (9/3 - 2/3) / (28/3)

=7/3 x 3/28

= 7/28

= 1/4

(2/3)/(5/6) - 2/5

= 2/3 x 6/5 - 2/5

= 12/15 - 2/5

= 4/5 - 2/5

= 2/5

(-3/4 + 1/2)/(2/5 - 5/2)

= (-3/4 + 2/4) / (4/10 - 25/10)

= (-1/4) / (-21/10)

= -1/4 x -10/21

= 10/84

= 5/42