bonjour pouvez-vous m'aider s'il vous plaît pour l'exercice 88 merci beaucoup de votre gentillesse et de votre patience cordialement

Bonjour,

(3 - 2/3) / (4/3 x 7) =
(9/3 - 2/3) / (28/3) =
7/3 x 3/28 =
3/3 x 7/(7x4) = 1/4

(2/3)/(5/6) - 2/5 =
2/3 x 6/5 - 2/5 =
6/3 x 2/5 - 2/5 =
2 x 2/5 - 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 =
(2 x 5)/(2 x 2) x 1/21 =
5/2 x 1/21 = 5/42

a. 3 - 2/3/4/3 x 3 = 1/4

N = 3 - 2/3 = 9/3 - 2/3 = 7/3
D = 4x 7/3

7/3/4 x 7/3 = 1/4 

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

2/3/5/6 = 2 x 6/3 x 5 = 4/5

4/5 - 2/5 = 2/5

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

N = - 3/4 + 1/2 = - 3/4 + 2/4 = - 1/4

D = 2/5 - 5/2  = 4/10 - 25/10 = - 21/10

-1/4/-21/10 = - 1 x 10/- 21 x 4 = 5/42