Réponses

2014-09-08T18:04:36+02:00
A = 1 - (2/3 + 1/4)
A = 1 - (2 x 4 / 3 x 4 + 1 x 3 / 4 x 3)
A = 1 - (8/12 + 3/12)
A = 1 - 11/12
A = 1 x 12 / 1 x 12 - 11/12
A = 12/12 - 11/12
A = 1/12

B = 3 - 5/2
      1 + 1/5
B = 3 x 2 / 1 x 2 - 5/2
       1 x 5 / 1 x 5 + 1/5
B = 6/2 - 5/2
     5/5 + 1/5
B = 1/2 : 6/5
B = 1/2 x 5/6
B = 5/12