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

问题描述:

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