4乘y的四次方减4乘x的立方乘y加0.2乘x方乘y方加xy立方减0.2x方乘y方-4y的四次方减x立方y x为-2,y为

4y⁴-4x³y+0.2x²y²+xy³-0.2x²y²-4y⁴-x³y x=-2,y=0.3
=-5x³y+xy³
=-5*(-2)³*0.3+(-2)*0.3³
=12-0.054
=11.946