Bonjour

Calculer et mettre sous forme irréductible, en détaillant, les expressions suivantes :

A = 2/5 + 3/4 x 7/15

A = (2 x 12) / (5 x 12) + 21/60

A = 24/60 + 21/60

A = 45/60

A = (15 x 3) / (15 x 4)

A = 3/4

B = (2/3)² + 1/5 x 4/3

B = 4/9 + 4/15

B = (4 x 5) / (9 x 5) + (4 x 3) / (15 x 3)

B = 20/45 + 12/45

B = 32/45

C = (2/3 - 1/2) / (5/4 - 4/5)

C = [(2 x 2) / (3 x 2) - (1 x 3) / (2 x 3)] / [(5x 5) / (4 x 5) - (4 x 4) / (5 x 4)]

C = (4/6 - 3/6) / (25/20 - 16/20)

C = 1/6 : 9/20

C = 1/6 x 20/9

C = 20/54

C = (2 x 10) / (2 x 27)

C = 10/27

D = 5/3 : 3/4 + 7/8

D = 5/3 x 4/3 + 7/8

D = 20/9 + 7/8

D = (20 x 8) / (9 x 8) + (7 x 9) / (8 x 9)

D = 160/72 + 63/72

D = 223/72.