Réponse :
Explications étape par étape :
Bonjour
A = 2 - 5/4 × 1/10
A = 2 - 5/40
A = 2 - 5 / (5 × 8)
A = 2 -1/8
A = 16/8 - 1/8
A = 15/8
B = 3/5 - 2/5 × 3/10
B = 3/5 - (2 × 3) / (5× 10)
B = 3/5 - (2×3)/(5×2×5)
B = 3/5 - 3/25
B = 15/25 - 3/25
B = 12/25
C = 3/5 - (2/5) / (3/10)
C = 3/5 - (2/5) × (10/3)
C = 3/5 - (2×10) /(5×3)
C = 3/5 - (2×5×2) /(5×3)
C = 3/5 - 4/3
C = 9/15 - 20/15
C = -11/15
D = (2/3 + 5/7) ×3/4 -3/4
D = (14/21 +15/21) × 3/4 - 3/4
D = (29/21) × 3/4 - 3/4
D = 87/84 - 3/4
D = 87/84 - 63/84
D = 24/84
D =12/42
D =2/7
b)
1/a + 1/b + 1/c
a = 2/3 b = -3/2 c = -3/4
1/(2/3) + 1/ (-3/2) + 1/(-3/4) = 3/2 -2/3 -4/3 = 3/2 - 6/3 = 3/2 - 2 = 3/2 - 4/2 = -1/2
