Réponse :

Bonsoir

Explications étape par étape

Exercice 2

A = 9x² - (6x +8)(6x -4)

A = 9x² - (36x² -24x +48x -32)

A = 9x² - (36x² +24x -32)

A = 9x² -36x² -24x +32

A = -27x² -24x +32

B = 4x - (7x +6)(3x -1) +7

B = 4x - (21x² -7x +18x -6) +7

B = 4x - (21x² +11x -6) +7

B = 4x -21x² -11x +6 +7

B = -21x² -7x +13

C = (3x +5)² + (3x +1)(6x +1)

C = 9x² +30x +25 + (18x² +3x +6x +1)

C = 9x² +30x +25 +18x² +9x +1

C = +27x² +39x +26

D = (x+3) (5x +4) - (x+9)(x-3)

D = 5x² +4x +15x +12 - (x² -3x +9x -27)

D = 5x² +19x +12 - (x² +6x -27)

D = 5x² +19x +12 -x² -6x +27

D = 4x² +13x +39