Bonsoir,
a)
F = (2x + 3) (x - 4) + (5x + 1) (2x + 7)
F = 2x² - 8x + 3x - 12 + 10x² + 35x + 2x + 7
F = 2x² + 10x² - 8x + 3x + 35x + 2x - 12 + 7
F = 12x² + 32x - 5
b)
G = (x - 7) (3x + 1) - (2x + 1) (3x - 4)
G = 3x² + 3x - 21x - 7 - (6x² - 8x + 3x - 4)
G = 3x² + 3x - 21x - 7 - 6x² + 8x - 3x + 4
G = 3x² - 6x² + 3x - 3x - 21x + 8x - 7 + 4
G = - 3x² - 13x - 3
c)
H = (7x - 6)² - (2x - 4) (5x - 7)
H = 49x² - 84x + 36 - (10x² - 14x - 20x + 28)
H = 49x² - 84x + 36 - 10x² + 14x + 20x - 28
H = 49x² - 10x² - 84x + 14x + 20x + 36 - 28
H = 39x² - 50x + 12
d)
Pour x = 0
F = (2x + 3) (x - 4) + (5x + 1) (2x + 7)
F = (2 * 0 + 3) (0 - 4) + (5 * 0 + 1) (2 * 0 + 7)
F = 3 * - 4 + 1 * 7
F = - 12 + 7
F = - 5
Pour x = - 2
F = (2x + 3) (x - 4) + (5x + 1) (2x + 7)
F = (2 * - 2 + 3) (- 2 - 4) + (5 * - 2 + 1) (2 * - 2 + 7)
F = (- 4 + 3) (- 6) + (- 10 + 1) (- 4 + 7)
F = - 1 * - 6 + - 9 * 3
F = 6 - 6
F = 0
e)
Pour x = 4
G = (x - 7) (3x + 1) - (2x + 1) (3x - 4)
G = (4 - 7) (3 * 4 + 1) - (2 * 4 + 1) (3 * 4 - 4)
G = - 3 * (12 + 1) - (8 + 1) (12 - 4)
G = - 3 * 13 - 9 * 8
G = - 39 - 72
G = - 111.
Pour x = - 4
G = (x - 7) (3x + 1) - (2x + 1) (3x - 4)
G = (- 4 - 7) (3 * - 4 + 1) - (2 * - 4 + 1) (3 * - 4 - 4)
G = - 11 * (- 12 + 1) - (- 8 + 1) (- 12 - 4)
G = - 11 * - 11 - (- 7) * - 16
G = 121 - 112
G = 9.
