Réponses

2013-11-19T18:24:05+01:00
A=7/5-7/3x15/14 = 21/15 - 35/15  x 15/14 = -14/15 x 15/14 = -1


B=8/5-3/4:9/8 = 8/5 - 3/4 x 8/9 = 8/5 - 24/36 = 288/180 - 120/180 = 168/180 = 40/45 = 8/9


C=8/3-2/5:7/5
= 8/3 - 2/5 x 5/7 = 8/3 - 2/7 = 56/21 - 6/21 = 50/21 = 4 + 6/21  = 4  + 2/7