Réponses

2014-09-03T13:40:15+02:00
1) Calculer sous la forme irréductible A= 4/5 - 7/6 × (1/4÷5/6)A = 4/5 - 7/6 x (1/4 x 6/5)
A = 4/5 - 7/6 x 6/20
A = 4/5 - 42/80
A = 4 x 16 / 5 x 16 - 42/80
A = 64/80 - 42/80
A = 22/80
A = 2 x 11 / 2 x 40
A = 11/40

B = 2/3 - 3/2
      2/5 + 5/2

B = 2 x 2 / 3 x 2 - 3 x 3 / 2 x 3
      2 x 2 / 5 x 2 + 5 x 5 / 2 x 5
B = 4/6 - 9/6
     4/10 + 25/10
B = - 5/6 : 29/10
B = - 5/6 x 10/29
B = - 50/174
B = 2 x - 25 / 2 x 87
B = - 25/87