Réponse :
A = (x + 3)(x + 2)
= x * x + x * 2 + 3 * x + 3 * 2
= x² + 2x + 3x + 6
= x² + 5x + 6
B = (x + 3)(2x + 4)
= x * 2x + x * 4 + 3 * 2x + 3 * 4
= 2x² + 4x + 6x + 12
= 2x² + 10x + 12
D = (x - 3)(4 - x)
= x * 4 - x * x - 3 * 4 - 3 * x
= 4x - x² - 12 - 3x
= -12 + 7x - x²
E = (3x + 4)(5x - 7)
= 3x * 5x - 3x * 7 + 4 * 5x + 4 * 7
= 15x² - 21x + 20x + 28
= 15x² - 28 - x
Bonjours
A = (x + 3) (x + 2)
A = X x X + X x 2 + 3 x X + 3 x 2
A = X2(au carré) + 2X + 3X + 6
A = X2(au carré) + 5x + 6
B = (x + 3) (2x + 4)
B = X x 2X + X x 4 + 3 x 2X + 3 x 4
B =2X2 (au carré) + 4X + 6X + 12
B = 2X2 (au carré) + 10X +12
C = (x - 3) (4 - x)
C = X x 4 + X x (-X) (-3) x 4 (-3) x -X
C = 4X - X2 (au carré) -12 + 3X
C = 4X - X2 (au carré) + 3X - 12
C = 4X + 3X - X2 (au carré) - 12
C = 7X - X2 (au carré) - 12
D = (3x + 4) (5x - 7)
D = 3X x 5X + 3X x (-7) + 4 x 5X + 4 x (-7)
D = 15X2 (au carré) - 21X + 20X -28
D = 15X2 (au carré) - X - 28
J'espère t'avoir aidé.