原式=3x^+(-3x/2+y^/3)(2x-2y/3)
=3x^-3x^+xy+(2/3)xy^-(2/9)y^3
=xy+(2/3)xy^-(2/9)y^3,
x=-1/3,y=2/3时
原式=-2/9-2/9*4/9-2/9*8/27
=-2/9*(1+4/9+8/27)
=-2/9*47/27
=-94/243.
希望对你能有所帮助.
原式=3x^+(-3x/2+y^/3)(2x-2y/3)
=3x^-3x^+xy+(2/3)xy^-(2/9)y^3
=xy+(2/3)xy^-(2/9)y^3,
x=-1/3,y=2/3时
原式=-2/9-2/9*4/9-2/9*8/27
=-2/9*(1+4/9+8/27)
=-2/9*47/27
=-94/243.
希望对你能有所帮助.