已知x³-y³=19,x²y+xy²=21求(x³+2y³)-2(x³-2xy²+x²y)+(y³+4x²y-2xy²-2x³)的值
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已知x³-y³=19,x²y+xy²=21求(x³+2y³)-2(x³-2xy²+x²y)+(y³+
已知x³-y³=19,x²y+xy²=21求(x³+2y³)-2(x³-2xy²+x²y)+(y³+4x²y-2xy²-2x³)的值
已知x³-y³=19,x²y+xy²=21
求(x³+2y³)-2(x³-2xy²+x²y)+(y³+4x²y-2xy²-2x³)的值
已知x³-y³=19,x²y+xy²=21求(x³+2y³)-2(x³-2xy²+x²y)+(y³+4x²y-2xy²-2x³)的值
(x³+2y³)-2(x³-2xy²+x²y)+(y³+4x²y-2xy²-2x³)
=x³+2y³-2x³+4xy²-2x²y+y³+4x²y-2xy²-2x³
=-3x³+3y³+2x²y+2xy²
=-3(x³-y³)+2(x²y+xy²)
=-3×19+2×21
=-57+42
=-15