svp repondez moi a cette reponce. merci d'avance

Bonsoir,

A = 3x (2 + 5x) + 2x + 1 = 15x² + 8x + 1
A = 6x + 15x² + 2x + 1 = 15x² + 8x + 1
A = 15x² + 8x + 1 = 15x² + 8x + 1

B = (2x + 1) (3x + 5) = 6x² + 13x + 5
B = 6x² + 10x + 3x + 5 = 6x² + 13x + 5
B = 6x² + 13x + 5 = 6x² + 13x + 5

C = 2x (- x + 1) - 1 = - 2x² + 6x + 1
C = - 2x² + 2x - 1 ≠ - 2x² + 6x + 1 - Pas d'égalité

D = 2x - (2x + 1) (3x + 5) = - 6x² - 11x - 5
D = 2x - (6x² + 10x + 3x + 5) = 6x² - 11x - 5
D = 2x - 6x² - 10x - 3x - 5 = 6x² - 11x - 5
D = - 6x² - 11x - 8 = 6x² - 11x - 5

E = 1 - 2x (x - 3) = - 2x² + 6x + 1
E = 1 - 2x² + 6x = - 2x² + 6x + 1
E = - 2x² + 6x + 1 = - 2x² + 6x + 1

F = - 2x (- x + 1) - 2x (x - 3) = - x² + 7x
F = 2x² - 2x - 2x² + 6x = - x² + 7x
F = 4x ≠ - x² + 7x - Pas d'égalité

G = (x + 1)² = x² + 2x + 1
G = x² + 2x + 1 = x² + 2x + 1

H = (x - 2)² = x² - 4x + 4
H = x² - 4x + 4 = x² - 4x + 4 

I = (x - 3) (x + 3) = x² - 9
I = x² + 3x - 3x - 9 = x² - 9
I = x² - 9 = x² - 9

J = (x - 3)² - (x + 3)² = - 12x
J = x² - 6x + 9 - (x² + 6x + 9) = - 12x
J = x² - 6x + 9 - x² - 6x - 9 = - 12x
J = - 12x = - 12x