Réponse:
1)
A = (x + 3)(2x - 1) + (x² - 9)
= x × 2x + x × (-1) + 3 × 2x + 3 × (-1) + x² -9
= 2x²- x + 6x- 3 + x²- 9
A = 3x² + 5x - 12
2)
B = x²-9
= x² - 3²
B = (x-3)(x+3)
3)
A = (x + 3)(2x - 1) + (x² - 9)
= (x + 3)(2x - 1) + (x - 3)(x + 3)
= (x + 3)×[(2x - 1)+(x - 3)]
= (x + 3)(2x - 1 + x - 3)
A = (x + 3)(3x - 4)
4)
A = (x + 3)(2x - 1) + (x² - 9) pour x=0
= (0+3)(2×0 -1)+(0²-9)
= 3 × (-1) + (-9)
= -3 - 9
A = -12
5)
A = (x + 3)(3x - 4) = 0
x + 3 =0 3x - 4=0
x = -3 3x = 4
[tex]x = - 3 \: \: \: \: x = \frac{4}{3} [/tex]
Explications étape par étape:
5 pts!!!
