Bonsoir, pouvez vous m’aidez pour l’exercice 7, 8 et 9

Bonsoir,

Exercice 7

E = 8/3 + 5 ÷ (1 - 2/5)

E = 8/3 + 5 ÷ (5/5 - 2/5)

E = 8/3 + 5 ÷ 3/5

E = 8/3 + 5 × 5/3

E = 8/3 + 25/3

E = 33/3

E = 11

F = (55 × 10³ × 2¹º)/(10⁴ × 2^9)

F = 55 × 10^(3 - 4) × 2^(10 - 9)

F = 55 × 10-¹ × 2¹

F = 110 × 10-¹

F = 110 × 0,1

F = 11

Donc on a E = F = 11

Exercice 8

Virus de la varicelle : 1 750 × 10^(-10) m 1,750 × 10³ × 10^(-10) = 1,750 × 10^(-7) m

Virus de la gastro entérite : 0,07 × 10^(-6) m = 7,0 × 10-² × 10^(-6) = 7,0 × 10^(-8) m

Virus de la fièvre : 40 × 10^(-9) = 4,0 × 10¹ × 10^(-9) = 4,0 × 10^(-8)

Ordre croissant :

4,0 × 10^(-8) < 7,0 × 10^(-8) < 1,750 × 10^(-7)

Exercice 9

Vitesse = Distance / Temps

Temps = Distance / Vitesse

Temps = (1,5 × 10^8)/(3 × 10^5) = 1,5/3 × 10^8/10^5 = 0,5 × 10^5 s = 1,5 × 10⁴ s

Produit en croix

60s = 1 min

1,5 × 10⁴ s = (1,5 × 10⁴) × 1/ 60 = 250 min