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bonjour
J'aurai besoin d'aide
&) Développer et réduire
A= 3(2x-1)
B= (4x-2)(5-x)
C= (7x+4)au carré
D= (9-x)(9+x)

2) Factoriser
E= 5x-25
F= (x+2)(y-1)+7(x+2)
G= 16xau carré +81-72x
H= 169-x au carré


Répondre :

1) A = 3 (2x - 1)
A = 3 * 2x + 3 * (- 1)
A = 6x - 3

B = (4x - 2) (5 - x)
B = 4x * 5 + 4x * (- x) - 2 * 5 - 2 * (- x)
B = 20x - 4x² - 10 + 2x
B = - 4x² + 22x - 10

C = (7x + 4)²
C = (7x)² + 2 * 7x * 4 + 4²
C = 49x² + 56x + 16

D = (9 - x) (9 + x)
D = 9² - x²
D = 81 - x²

2) E = 5x - 25
E = 5 * x - 5 * 5
E = 5 (x - 5)

F = (x + 2) (y - 1) + 7 (x + 2)
F = (x + 2) [(y - 1) + 7]
F = (x + 2) (y - 1 + 7)
F = (x + 2) (y + 6)

G = 16x² + 81 - 72x
G = (4x)² + 9² - 2 * 36 * x
G = (4x - 9)²

H = 169 - x²
H = 13² - x²
H = (13 - x) (13 + x)