已知A=2x²+3xy-y²,B=-1/2xy,C=1/8x³y³-1/4x²y^4.求:2AB²-C

已知A=2x²+3xy-y²,B=-1/2xy,C=1/8x³y³-1/4x²y^4.求:2AB²-C
已知A=2x²+3xy-y²,B=-1/2xy,C=1/8x³y³-1/4x²y^4.求:2AB²-C

已知A=2x²+3xy-y²,B=-1/2xy,C=1/8x³y³-1/4x²y^4.求:2AB²-C
2AB²-C
=2(2x²+3xy-y²)(-1/2xy)²-(1/8x³y³-1/4x²y^4)
=2(2x²+3xy-y²)(x²y²)/4-(1/8x³y³-1/4x²y^4)
=x^4y^2+3/2*x^3y^3-1/2*x^2y^4-(1/8x³y³-1/4x²y^4)
=x^4y^2+11/8*x^3y^3-1/4*x^2y^4
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