Réponse:
A=x²+2×x×3+3²
=x²+6x+9
B=x²-4²
=x²-16
C=x²-2×x×5+5²
=x²-10x+25
C=6-3×2x-3×1
=6-6x-3
=-6x-3
D=5x×3x+5x×2-4×3-4×2
=15x²+10x-12-8
=15x²+10x-2p
