Bonjour je n'arrive pas ceci c'est pour lundi Factoriser les expressions ci-dessous A=4x(x+2)+3(x+2) B=3y(y+6)+7(y+6) C=(4x-3)(2x+1)-5x(4x-3) D=4x²+8x+4 J=(x+3)

Bonjour

A = 4x(x+2)+3(x+2)
A = (x+2)(4x+3)

B = 3y(y+6)+7(y+6)
B = (y+6)(3y+7)

C = (4x-3)(2x+1)-5x(4x-3)
C = (4x-3)[(2x+1)-5x]
C = (4x-3)(-3x+1)

D = 4x²+8x+4
D = (2x)² + 2×2x×2 + 2²
D = (2x+2)²

J = (x+3)²-64
J = (x+3)² - 8²
J = (x+3-8)(x+3+8)
J = (x-5)(x+11)

♤ Resoudre :
6x - 7 = 8
6x = 15
x = 15/6

2x - 11 = 7x + 4
2x - 7x = 4 + 11
- 5x = 15
x = 15/-5 = - 3

6 - 3x = 15 + 4x
- 3x - 4x = 15 - 6
- 7x = 9
x = 9/7



Voilà ^^

Bonjour,

A = 4x(x + 2) + 3(x + 2)
A = (x + 2)(4x + 3)

B = 3y(y + 6) + 7(y + 6)
B = (y + 6)(3y + 7)

C = (4x - 3)(2x + 1) - 5x(4x - 3)
C = (4x - 3)(2x + 1 - 5x)
C = (4x - 3)(-3x + 1)

D = 4x^2 + 8x + 4
D = (2x)^2 + 2 * 2x * 2 + (2)^2
D = (2x + 2)^2

J = (x + 3)^2 - 64
J = (x + 3 - 8)(x + 3 + 8)
J = (x - 5)(x + 11)

Ce ne serait pas résoudre plus tôt que factoriser ?

6x - 7 = 8
6x = 8 + 7
6x = 15
x = 15/6

2x - 11 = 7x + 4
7x - 2x = - 11 - 4
5x = -15
x = -15/5
x = -3

6 - 3x = 15 + 4x
4x + 3x = 6 - 15
7x = -9

x = -9/7