Bonjour je suis en 4ème et j'ai besoin d'aide pour mes exercices de maths le 4 et 5​

Réponse :

Explications étape par étape

Bonjour

Exercice 4 :

9/7 x 14/15

= 9/15 x 14/7

= (3 x 3)/(3 x 5) x (2 x 7)/7

= 3/5 x 2

= 6/5

7/8 x 3/14 x 4/9

= 7/14 x 4/8 x 3/9

= 7/(2 x 7) x 4/(2 x 4) x 3/(3 x 3)

= 1/2 x 1/2 x 1/3

= 1/12

17/81 x 9/8 x 7/34 x 64/70

= 17/34 x 9/81 x 64/8 x 7/70

= 17/(2 x 17) x 9/(2 x 9) x (8 x 8)/8 x 7/(7 x 10) = 1/2 x 1/2 x 8 x 1/10

= 8/40

= 8/(5 x 8)

= 1/5

Exercice 5 :

A = 63/40 x 5/42

A = (9 x 7 x 5)/(8 x 5 x 6 x 7)

A = 9/48

B = 3/20 x 80/27

B = (3 x 20 x 4)/(20 x 3 x 9)

B = 4/9

C = 45/64 x 64/81

C = (9 x 5 x 64)/(64 x 9 x 9)

C = 5/9

D = 14/15 x 20/49

D = (2 x 7 x 4 x 5)/(3 x 5 x 7 x 7)

D = 8/21

E = 3/50 x 10/9

E = (3 x 10)/(5 x 10 x 3 x 3)

E = 1/15

F = 20/63 x 81/8

F = (5 x 4 x 9 x 9)/(9 x 7 x 2 x 4)

F = 45/14

G = 27/40 x 32/45

G = (3 x 9 x 8 x 4)/(8 x 5 x 9 x 5)

G = 12/25

H = 27/16 x 56/27

H = (27 x 8 x 7)/(2 x 8 x 27)

H = 7/2