2xy(½x2y-2y2x) (3x²y+4xy²-x³y³)×（-xy³）²

2xy(½x2y-2y2x) (3x²y+4xy²-x³y³)×（-xy³）²
2xy(½x2y-2y2x) (3x²y+4xy²-x³y³)×（-xy³）²

2xy(½x2y-2y2x) (3x²y+4xy²-x³y³)×（-xy³）²
2xy(½x²y-2y²x)
=2xy×½x²y-2xy×2y²x
=2×½×(x×x²)×(y×y)-2×2×(x×x)×(y×y²)
=x³y²-4x²y³

(3x²y+4xy²-x³y³)×(-xy³)²
=(3x²y+4xy²-x³y³)×x²y^6
=3x²y×x²y^6+4xy²×x²y^6-x³y³×x²y^6
=3×(x²×x²)×(y×y^6)+4×(x×x²)×(y²×y^6)-(x³×x²)×(y³×y^6)
=3x^4y^7+4x³y^8-x^5y^9