Bonsoir,

1) Z = (12x + 3) (2x - 7) + (2x - 7)²

Z = 24x² - 84x + 6x - 21 + 4x² - 28x + 49

Z = 24x² + 4x² - 84x - 28x + 6x + 49 - 21

Z = 28x² - 106x + 28

2) Z = (12x + 3) (2x - 7) + (2x - 7)²

Z = (2x - 7) (12x + 3 + 2x - 7)

Z = (2x - 7) (14x - 4)

Z = 2 (2x - 7) (7x - 2)

3) Poux = 2

Z = 28x² - 106x + 28

Z = 28 * 2² - 106 * 2 + 28

Z = 28 * 4 - 212 + 28

Z = 112 - 212 + 28

Z = - 72

Pour x = - 1

Z = 28x² - 106x + 28

Z = 28 * - 1² - 106 * - 1 + 28

Z = 28 * 1 + 106 + 28

Z = 28 + 28 + 106

Z = 162.