Réponse :

EX1  simplifier le plus possible

a) - 9/12 = - 3 x 3/3 x 4 = - 3/4

b) - 10/-12 = - 2 x 5/- 2 x 6 = 5/6

c) 25/75  = 25/3 x 25 = 1/3

d) - 3/24 = - 3/3 x 8  = - 1/8

e) - 42/63 = - 6 x 7/7 x 9 = - 6/9 = - 2/3

f) 27/-81 = 3 x 9/- 9 x 9 = 3/- 9 = - 1/3

EX2  calculer a , b , c et d , les résultats seront donnés sous forme de fraction irréductible

a = 5/6 + 3/4 = 10/12 + 9/12 = 19/12

b = 5/6 + 3/4 - 2/3  = 19/12 - 8/12 = 11/12

c = 35/36 x 4/7 x 9/10 = 5 x 7/4 x 9) x 4/7 x 9/10 = 1/2

d = (6/5 + 4/3 - 3/2)(1/8 - 5/3) = (36/30 + 40/30 - 45/30)(3/24 - 40/24)

  = 31/30 x (- 37/24 = - 1147/720  

EX3   simplifier

a = 1/3/2  = 2/3

b = 1/3/2 = 1/6

c = 1/(1/2 + 1/3) = 1/5/6  = 6/5

d = (3/2 - 5/6)/(1/4 + 1/3) = (9/6 - 5/6)/(3/12 + 4/12) = 4/6/7/12 = 2/3/7/12

  = 2 x 12)/3 x 7  = 8/7

e = 4 - 2/3)/4  = (12/3 - 2/3)/4 = 10/3/4  = 10/12 = 5/6

Explications étape par étape :