Réponse :
L = -7x(2 - x) + (2x + 1)(2x - 1)
L = -7x*2 -7x*(-x) + 2x*2x + 2x*(-1) + 1*2x + 1*(-1)
L = -14x + 7x² + 4x² - 2x + 2x - 1
L = 11x² - 14x - 1
M = (4x + 1)(4x - 1) - (3x? - 2)
M = 4x*4x + 4x*(-1) + 1*4x + 1*(-1) - (3x? - 2)
M = 16x² - 4x + 4x - 1 - (3x? - 2)
M = 16x² - 1 - (3x? - 2)
N = (3 - 4x)(3 + 4x) - (1 - 2x)(6 + x)
N = 3*3 + 3*4x - 4x*3 - 4x*4x - (1*6 + 1*x - 2x*6 - 2x*x)
N = 9 + 12x - 12x - 16x² - (6 + x - 12x - 2x²)
N = 9 - 16x² - 6 + 11x + 2x²
N = - 14x² + 11x + 3
