Bonjour,
Explications étape par étape :
A = 7/3 - 4/3 : 8/5
A = 7/3 - 4/3 x 5/8
A = 7/3 - 4/8 x 5/3
A = 7/3 - 4/(2 x 4) x 5/3
A = 7/3 - 1/2 x 5/3
A = 7/3 - 5/6
A = (7 x 2)/(3 x 2) - 5/6
A = 14/6 - 5/6
A = 9/6
A = (3 x 3)/(2 x 3)
A = 3/2
B = -4/9 x 1/5 : 3/7
B = -4/45 x 7/3
B = -28/135
C = -8/3 : -5/6 + 7/4
C = -8/3 x -6/5 + 7/4
C = 6/3 x 8/5 + 7/4
C = (3 x 2)/3 x 8/5 + 7/4
C = 2 x 8/5 + 7/4
C = 16/5 + 7/4
C = (16 x 4)/(5 x 4) + (7 x 5)/(4 x 5)
C = 64/20 + 35/20
C = 99/20
Réponse :
A = 3/2
B = -28/135
C = 99/20