developper et reduire : exercice 23

Bonjour,

(2x-5)(-7-4x) = -14x-8x²+35+20x = -8x²+6x+35

2x-5(-7-4x) = 2x+35+20x = 22x+35

(2x-5)-(-7-4x) = 2x-5+7+4x = 6x+2

2x(1-x)-(x-3)(3x+2) = 2x-2x²-(3x²+2x-9x-6) = -2x²-3x²+2x-2x+9x+6 = -5x²+9x+6