-0.2a的3x+2次方b的3次方与1/2ab的y次方是同类项3x+2=1 y=3x=-1/3 y=3代数式3xy平方-[2x平方y-2(xy-3/2xy平方）+xy]+3x平方y=3xy^2-[2x^2y-2xy+3xy^2+xy]+3x^2y=3xy^2-2x^2y+xy-3xy^2+3x^2y=x^2y+xy=xy(x+1)=-1/3*3(...