Bonsoir, pouvez vous m'aider ? Merci d'avance 1) (-X+3)(4X-4)+16X²-16 - Develloper, - Factoriser, - A=? | x=3/10 (fraction) - A=0 | x=? 2) (2X+9)²+(9X+6)(2X+9)

Réponse :

Explications étape par étape

Bonsoir

(-X+3)(4X-4)+16X²-16

- Develloper,

= -12x^2 + 4x + 12x - 12 + 16x^2 - 16

= 4x^2 + 16x - 28

- Factoriser,

= (-x - 3)(4x - 4) + (4x)^2 - 4^2

= (-x - 3)(4x - 4) + (4x - 4)(4x + 4)

= (4x - 4)(-x - 3 + 4x + 4)

= 4(x - 1)(3x + 1)

- A=? | x=3/10 (fraction)

A = 4(3/10 - 1)(3 * 3/10 + 1)

A = 4(3/10 - 10/10)(9/10 + 10/10)

A = 4(-7/10)(19/10)

A = -7/5 * 19/5

A = -133/25

- A=0 | x=?

4(x - 1)(3x + 1) = 0

x - 1 = 0 ou 3x + 1 = 0

x = 1 ou 3x = -1

x = 1 ou x = -1/3

2)

(2X+9)²+(9X+6)(2X+9)

- Develloper

= 4x^2 - 36x + 81 + 18x^2 + 81x + 12x + 54

= 22x^2 + 57x + 135

- Factoriser​

= (2x + 9)(2x + 9 + 9x + 6)

= (2x + 9)(11x + 15)