Calculer de deux manieres différentes : A = 3/4 (1/2-4/5) attention pas -4 B = 1/2 x 3/8 + 1/2x5/6

A = 3/4 (1/2 - 4/5)
A = 3/4 (1 x 5 / 2 x 5 - 4 x 2 / 5 x 2)
A = 3/4 (5/10 - 8/10)
A = 3/4 (- 3/10)
A = - 9/40

ou
A = 3/4 (1/2 - 4/5)
A = 3/8 - 12/20
A = 3 x 5 / 8 x 5 - 12 x 2 / 20 x 2
A = 15/40 - 24/40
A = - 9/40

B = 1/2 x 3/8 + 1/2 x 5/6
B = 3/16 + 5/12
B = 3 x 3 / 16 x 3 + 5 x 4 / 12 x 4
B = 9/48 + 20/48
B = 29/48

ou

B = 1/2 x 3/8 + 1/2 x 5/6
B = 1/2 x (3/8 + 5/6)
B = 1/2 x (3 x 3 / 8 x 3 + 5 x 4 / 6 x 4)
B = 1/2 x (9/24 + 20/24)
B = 1/2 x 29/24
B = 29/48