Réponses

2014-10-14T18:37:27+02:00
B = 4/5 + 8/15
B = 4x3/(5x3) + 8/15
B= 12/15 + 8/15
B = 20/15
B = 4/3

C = 2/3 + 5/3 x 5/4
C = 2x4/(3x4) + 5x5/(3x4)
C = 8/12 + 25/12
C = 33/12
2014-10-14T19:27:28+02:00
B = 4 / 5 + 8 / 15
= 12 / 15 + 8 / 15 
= 20 / 15
= 4 / 3

C = 2 / 3 + 5 / 3 x 5 / 4
= 2 / 3 + 25 / 12
= 8 / 12 + 25 / 12
= 33 / 12
= 11 / 4