Sagot :
Bonjour. Voilà pour l'exercice 1 déjà.
Exercice 1 :
A = 6/5 × 2/3 = 12/15 = (3 × 4)/(3 × 5) = 4/5
B = -5/3 × -7/-6 = -5/3 × 7/6 = -35/18
C = -40/72 × 54 = -(8 × 5)/(8 × 9) × 54 = 5/9 × 54 = -5/9 × (6 × 9) = -(5 × 6 × 9)/9 = -5 × 6 = -30
D = -(-7)/6 × 4/-3 = 7/6 × (-4/3) = -28/18 = -(2 × 14)/(2 × 9) = -14/9
E = 15/16 × -24/25 = -(15 × 24)/(16 × 25) = -(3 × 5 × 2 × 12)/(2 × 8 × 5 × 5) = -(3 × 12)/(8 × 5) = -(3 × 3 × 4)/(2 × 4 × 5) = -(3 × 3)/(2 × 5) = -9/10
F = -35/-18 × -36/42 = 35/18 × -36/42 = -(35 × 36)/(18 × 42) = -(7 × 5 × 2 × 18)/(18 × 6 × 7) = -(5 × 2)/6 = -(5 × 2)/(3 × 2) = -5/3
G = -25/-49 × -63/40 × 64/-45 = 25/49 × -63/40 × 64/-45 = -(25 × 63 × 64)/-(49 × 40 × 45) = (25 × 63 × 64)/(49 × 40 × 45) = (5 × 5 × 7 × 9 × 8 × 8)/(7 × 7 × 8 × 5 × 9 × 5) = 8/7
En te souhaitant une bonne journée :)