Bonsoir, le bonus svp merci

Bonjour,

h (x) = (2 - 3x)² - 2 (2 - 3x) (2x + 1) - (x + 1) (x - 1)
h (x) = 4 - 12x + 9x² - 2 (4x + 2 - 6x² - 3x) - (x² - 1)
h (x) = 4 - 12x + 9x² - 8x - 4 + 12x² + 6x - x² + 1
h (x) = 9x² + 12x² - x² - 12x - 8x + 6x + 4 - 4 + 1
h (x) = 20x² - 14x + 1