Réponse :

III. A(x) = (3x - 4)² - 2(3x - 4x)(x + 8) + (3x - 4)

1) A(x) = (3x - 4)(3x - 4) - 2 (3x² + 24x - 4x² - 32x) + 3x - 4

A(x) = 9x² - 12x - 12x + 16 - 6x² - 48x + 8x² + 64x + 3x - 4

A(x) = 11x² - 5x + 12

2) A(x) =

3)* A(0) =+ 12

*A(4/3) = 11(16/9) - 5(4/3) + 12 = 176/9 - 20/3 + 12 =176/9 - 60/9 + 12 = 116/9 + 12 =116/9 + 108/9 = 224/9

*A(racine carrée de2) = 11x2 - 5racinede2 + 12 = 34 +- 5racine carrée de 2

4) A(x) = 0

11x² - 5x + 12 = 0

11x² = 5x + 12

x² = (5x + 12)/11

x = racine carrée de (5x+12)/11

Explications étape par étape