bjr
D=(2x-5)(3x-2)
=2x*3x + 2x*(-2) - 5*3x - 5*(-2)
= 6x² - 4x - 15x +10
= 6x² - 19x + 10
E=(2x+3)(5x-8)-(2x-4)(5x-1)
= 2x*5x + 2x*(-8) + 3*5x + 3*(-8) - (2x*5x + 2x*(-1) - 4*5x - 4*(-1))
= 10x² - 16x + 15x - 24 - (10x² - 2x - 20x + 4)
= 10x² - x - 24 - 10x² + 22x - 4
= 21x - 28
F=(5x-2)(5x-8)-(3x-5)(x+7) G=2(x+7)(3-2x)+(5x-2)(4x+1) => voir le E
