Réponses

2013-09-14T13:18:44+02:00
A: 12/5-4/5=8/5
b : 2/7-20/21=6/21-20/21=-14/21=-2/3
c : 6/5+(1/15-3/15)=6/5+(-2/15)=18/15-2/15=16/15
d : 6/20-2/(7/7-2/7)=6/20-2/(5/7)=6/20-2/1/(5/7)=6/20-2/1x7/5=6/20-14/5=6/20-56/20=-50/20=-5/2
2013-09-14T13:19:09+02:00
A = 2 x 6/5 - 4/5 
A = 12/5 - 4/5
A = 8/5

B = 2/7 - 2/7 x 10/3
B = 2/7 - 20/21 
B = 6/21 - 20/21
B = -14/21
B = -2/3

C = 6/5 + (1/15 - 1/5)
C = 6/5 + (1/15 - 3/15)
C = 6/5 - 2/15
C = 18/15 - 2/15
C = 16/15