Bonsoir Merci pour tous ceux qui répondront 19,20 et 21

Ex 19 :

a)
A= 4/5 + 2/5 = 6/5
B= 14/11 - 8/11 = 6/11
C= 5/7 + 13/7 = 18/7

b)
A= 34/9 - 23/9 = 11/9
B= 49/2 + 50/2 = 99/2
C= 14/25 - 10/25 = 4/25

Exercice 20 :

A= 1/2 + 3/4 = 2/4 + 3/4 = 5/4
B= 1/12 + 5/6 = 1/12 + 10/12 = 11/12
C= 7/5 - 14/10 = 14/10 - 14/10 = 0/10 = 0

Exercice 21 :

A= 2 + 1/2 = 4/2 + 1/2 = 5/2
B= 3 - 1/2 = 6/2 - 1/2 = 5/2
C= 2 + 1/3 = 6/3 + 1/3 = 7/3

Exercice 19 :
a) A = 4/5 + 2/5 = 6/5
    B = 14/11 - 8/11 = 6/11
    C = 5/7 + 13/7 = 18/7

b) A = 34/9 - 23/9 = 11/9
    B = 49/2 + 50/2 = 99/2 
    C = 14/25 - 10/25 = 4/25

Exercice 20 :
A = 1/2 + 3/4 
   = 2/4 + 3/4
   = 5/4

B = 1/12 + 5/6
   = 1/12 + 10/12
   = 11/12

C = 7/5 - 14/10
   = 14/10 - 14/10
   = 0

Exercice 21 :
A = 2 + 1/2
   = 2/1 + 1/2
   = 4/2 + 1/2
   = 5/2

B = 3 - 1/2
    = 3/1 - 1/2
    = 6/2 - 1/2
    = 5/2

C = 2 + 1/3
    = 2/1 + 1/3
    = 6/3 + 1/3
    = 7/3