Réponses

2014-04-11T19:58:51+02:00

exercice 1

A=7/3-3/7=(49-9)/21=40/21

B=10/33-3/22=(220-99)/726=121/726

C=(22/49)*(25/33)*(28/15)=(22*25*28)/(49*33*15)=(2*11*5*5*4*7)/(7*7*3*11*3*5)=(2*5*4)/(7*3*3)=40/73    (les chiffres en gras s'annule vu que c'est des multiplication)

E=5/7+(8/7:6/5)=5/7+(8*5)/(7*6)=5/7+40/42=(30+40)/42=70/42=35/21

F=(13/15)/(21/54)=(13*54)/(15*21)=702/315=78/35 (même principe)

exercice 2

G=(12x-6x²-20+10x)-(3x²+15x-x-5)=22x-6x²-20-3x²-14x+5=-9x²+8x-15

x=4

-9*4²+8*4-15=7+32-15=24

G(4)=24

Meilleure réponse !
2014-04-11T20:05:34+02:00
Salut :)

A = 7/3 - 3/7
A = 49/21 - 9/21
A = 40/49

B = 10/33 - 3/22
B = 20/66 - 9/66
B = 11/66
B = 1/6

C = 22/49 x 25/33 x 28/15
C = 11 x 2 x 5 x 5 x 7 x 4 / 7 x 7 x 3 x 11 x 3 x 5
C = 40/63

E = 5/7 + 8/7 : 6/5
E = 5/7 + 8/7 x 5/6
E = 5/7 + 2 x 4 x 5 / 7 x 3 x 2
E = 5/7 + 20/21
E = 15/21 + 20/21
E = 35/21
E = 5/3

F = (5 - 2/3) : (1/6 + 2/9)
F = (15/3 - 2/3) : (3/18 + 4/18)
F = 13/3 : 7/18
F = 13/3 x 18/7
F = 78/7

J'espère t'avoir aidé(e) ! :)