Bonjour pouvez vous m'aider svp c'est l'ex 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 : 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

= (3 x 4) / (3 x 5) - 2/5

= 4/5 - 2/5

= 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.