Réponse :
Explications étape par étape
Bonjour
1)
(-X+3)(4X-4)+16X²-16
- Develloper,
= -4x^2 + 4x + 12x - 12 + 16x^2 - 16
= 12x^2 + 16x - 28
- Factoriser,
= (-x + 3) * 4(x - 1) + (4x)^2 - 4^2
= 4(-x + 3)(x - 1) + (4x - 4)(4x + 4)
= 4(-x + 3)(x - 1) + 4(x - 1) * 4(x + 1)
= 4(-x + 3)(x - 1) + 16(x - 1)(x + 1)
= 4(x - 1)(-x + 3 + 4(x + 1))
= 4(x - 1)(-x + 3 + 4x + 4)
= 4(x - 1)(3x + 7)
- A=? | x=3/10 (fraction)
A = 12(3/10)^2 + 16 * 3/10 - 28
A = 12 * 9/100 + 24/5 - 28
A = 27/25 + 120/25 - 700/25
A = -553/25
- A=0 | x=?
A = 4(x - 1)(3x + 7) = 0
Produit de facteur nul :
x - 1 = 0 ou 3x + 7 = 0
x = 1 ou 3x = -7
x = 1 ou x = -7/3
2)
(2X+9)²+(9X+6)(2X+9)
- Develloper
= 4x^2 + 36x + 81 + 18x^2 + 81x + 12x + 54
= 22x^2 + 129x + 135
- Factoriser
= (2x + 9)(2x + 9 + 9x + 6)
= (2x + 9)(11x + 15)
