Răspuns :
x²+2y²-3x²+y²=3y²-2x²
12x+y-x+5y=11x+6y
a²+3ab-2a²+5ab²=5ab²-a²+3ab
-31a³bc²+5b²+20a³bc²-4b²=b²-11a³bc²
p²+2q²r+5p²-3q²=6p²+2q²r-3q²
3xyz+xy²z-6xyz+5xy²z=6xy²z-3xyz
12x+y-x+5y=11x+6y
a²+3ab-2a²+5ab²=5ab²-a²+3ab
-31a³bc²+5b²+20a³bc²-4b²=b²-11a³bc²
p²+2q²r+5p²-3q²=6p²+2q²r-3q²
3xyz+xy²z-6xyz+5xy²z=6xy²z-3xyz