Bonsoir j'ai besoin d'aide pour l'exercice 30 et 31 je ne comprend svp

Bonsoir,

Exercice 30

A=  (2/3)/4 = 2/ 3*4   = 2/12  =1/6

B= 2/(2/3)  = (2*3) /2 = 6/2 = 3

C=

1/2 -1/4 = 2/4 -1/4 = 1/4

(1/4)/(1/4 ) = 1

D= 2/3 -1 = 2/3 - 3/3 = -1/3

2/3+1 = 2/3 +3/3 = 5/3

(-1/3) / (5/3) = (-1*3)/ (3*5) = -3/15

Exercice 31

A=9/12 -8/12 +18/12 = 19/12

B= 3/4 -6/6 = 3/4 -1 = 3/4 -4/4 = -1/4

C= 3/(1/2) = 6

6*3/2 = 18/2 = 9

D=  1-1/2 = 2/2 -1/2 = 1/2

5*1/6 = 5/6