A=4x²+14x-2x-7=4x²+12x-7
B=-6x²-4x-9x-6=-6x²-13x-6
C D E les réponses sont bonnes
F=6(x²+9-6x)-(x²+2+x+2x)=
6x²+54-36x-x²-2-3x=
5x²-39x+52
G=2x²-3x-12x+18-(-6x²+27x-2x+9)=
2x²-3x-12x+18+6x²-27x+2x-9=
8x²-40x+9
H=x²+1+2x+(2x²-8x+3x-12)=
3x²-3x-11
I=9x²-30x+25-(x²+49+14x)=
9x²-30x+25-x²-49-14x=
8x²-44x-24
J=16-x²-(16x²+1-8x)=
16-x²-16x²-1+8x=
-17x²+8x+15