4x²y-8xy²+7-4x²y+10xy²-4
=(4-4)x²y+(-8+10)xy²+(7-4)
=2xy²+3
-4x²-5y²-5x+3y-9-4y+3+x²+5x
=(-4+1)x²-5y²+(-5+5)x+(3-4)y+(-9+3)
=-3x²-5y²-y-6
3x²-1-2x-5+3x-x²
=(3-1)x²+(-2+3)x+(-1-5)
=2x²+x-6
4x²y-8xy²+7-4x²y+10xy²-4
=(4-4)x²y+(-8+10)xy²+(7-4)
=2xy²+3
-4x²-5y²-5x+3y-9-4y+3+x²+5x
=(-4+1)x²-5y²+(-5+5)x+(3-4)y+(-9+3)
=-3x²-5y²-y-6
3x²-1-2x-5+3x-x²
=(3-1)x²+(-2+3)x+(-1-5)
=2x²+x-6