Réponse :
Explications étape par étape
Bonsoir
A: 14/15-7/20+-1/6
B: 7/5-3/5x4/21
C: (4/3-3/10):(5/2-2/5)
Calculer ces expressions et donner les résultats sous forme de fraction irreductibles
A = 14/15 - 7/20 - 1/6
A = (14 x 8)/(15 x 8) - (7 x 6)/(20 x 6) - (1 x 20)/(6 x 20)
A = 112/120 - 42/120 - 20/120
A = 50/120
A = 5/12
B = 7/5 - 3/5 x 4/21
B = 7/5 - 3/21 x 4/5
B = 7/5 - 1/7 x 4/5
B = 7/5 - 4/35
B = (7 x 7)/(5 x 7) - 4/35
B = 49/35 - 4/35
B = 45/35
B = (5 x 9)/(5 x 7)
B = 9/7
C = (4/3 - 3/10) / (5/2 - 2/5)
C = (40/30 - 9/30)/(25/10 - 4/10)
C = 31/30 / (21/10)
C = 31/30 x 10/21
C = 10/30 x 31/21
C = 1/3 x 31/21
C = 31/63