Réponse :
Bonjour,
a) (3x - 2)(5 - x) - 4x(x + 6)
= 15x - 3x² - 10 + 2x - (4x² + 24)
= -3x² + 15x + 2x - 10 - 4x² - 24
= -3x² - 4x² + 15x + 2x - 10 - 24
= -7x² + 17x - 34
b) -3(2 - 2x)(6 - 2x)
= (-6 + 6x)(6 - 2x)
= -36 + 12x + 36x - 12x²
= -12x² + 48x - 36
c) 2(x + 3)(5x + 1)
= (2x + 6)(5x + 1)
= 10x² + 2x + 30x + 6
= 10x² + 32x + 6
d) -2(x² + 1)(x - 2)
= (-2x² - 2)(x - 2)
= -2x³ + 4x² - 2x + 4
