Bonjour, j'aurais besoin d'aide pour l'exercice 3 svp ! Urgent !

bonsoir,
E=(3x+5)(2x+4)+(4x+2)(3x+5)
=6x²+12x+10x+20+12x²+20x+6x+10
=18x²+48x+30

F=(4x+8)(3x-2)+(4-2x)(5+4x)
=16x²-8x+24x-16+20+16x-10x-8x²
=8x²+22x+4

G=(5x-3)(2x+6)-(6x+5)(4x+2)
=10x²+30x-6x-18-(24x²+12x+20x+10)
=10x²+30x-6x-18-24x²-12x-20x-10
=-14x²-8x-28

H=(4-5x)(-2x+7)-(2x-4)(5x-3)
=-8x+28+10x²-35x-(10x²-6x-20x+12)
=-8x+28+10x²-35x-10x²+6x+20x-12
=-1x16