Bonjour,
1) Calculer et simplifier en détaillant :
A= 2/3x27/14-(4/5+5/3-1)
A = 54/42 - [(4 x 3) / (5 x 3) + (5 x 5) / (3 x 5) - (1 x 15) / (1 x 15)]
A = (6 x 9) / (6 x 7) - (12/15 + 25/15 - 15/15)
A = 9/7 - 2/15
A = (9 x 15) / (7 x 15) - (2 x 7) / (15 x 7)
A = 135/105 - 14/105
A = 121/105