Réponse :

Explications étape par étape

Bonsoir

A = 5/7 + 21/7 x 1/9

A = 5/7 + 21/9 x 1/7

A = 5/7 + 7/3 x 1/7

A = 5/7 + 7/21

A = 15/21 + 7/21

A = 22/21

B = (-8x + 7)^2

B = 64x^2 - 112x + 49

C = x^2 - (3x - 1)(x - 7)

C = x^2 - (3x^2 - 21x - x + 7)

C = x^2 - 3x^2 + 22x - 7

C = -2x^2 + 22x - 7

D) 4x - 8 < 8x + 4

-4 - 8 < 8x - 4x

-12 < 4x

x > -12/4

x > -3