Exercice 1
(x2 = x carré )
A = 3(4x+7) + 4(2x-9)
= 12x + 21 + 8x - 36
= 20x - 15
B = 7x(2x-5) - x(2x-5)
= 14x2 - 35x - 2x2 - 5x
= 12x2 - 40x
C = (2x+3)(5x-8)
= 10x2 - 16x + 15x -24
= 10x2 - x - 24
D = (3x-4)(8x-1)
= 24x2- 3x- 32x + 4
= 24x2 - 35x + 4
