x=2 y=1/2所以xy=1所以(3xy²)³*[xy(2x-y)-2x(xy-y²)]=(3y)³*[(2x-y)-2x(1-y²)]=27y³*(2x-y-2x+2xy²)=27y³*(-y+2y)=27y⁴=27*(1/2)⁴=27/16如果不懂,祝学习愉快!...