-3x2y+2x2y+3xy2-2xy2

3x2y+xy2-[2xy2-4x2y+(x2y-2xy2)] 5xy2-【3xy2-(4xy2-2x2y)】+2x2y】+2x2y-xy2 化简,再求值 -3x2y+2x2y+3xy2-2xy2 -3x2+2x2y+xy2 -2x2y(-2xy2)2+(2xy)3×( xy2) (x2y)3 × (-xy2)3 化简：5（3x2y-xy2) * (xy2+3x2y) x3-2x2y+xy2-x 因式分解:x3-2x2y+xy2 (6x2y-xy2-1/2x2y3)/(-3xy) （-1/2x2y）`（-3xy2）= 4xy2-4x2y-y3 （2 3 是方） （3x2y-2xy2）-（xy2-2x2y）,其中x=-1,y=2． 若m=x3-3x2y+2xy2+3y2 n=x3-2x2y+xy2-5y3,则2x3-7x2y+5xy2+14y2等于( )若m=x3-3x2y+2xy2+3y2 n=x3-2x2y+xy2-5y3,则2x3-7x2y+5xy2+14y2等于( )空里用字母表示 x.y取何值时,代数(x3y+3x2y-5xy2+6y3)+(y3+2xy2+x2y-2x3)-(4x2y-x3-3xy2+7y3).y取何值时，代数（x3y+3x2y-5xy2+6y3）+（y3+2xy2+x2y-2x3）-（4x2y-x3-3xy2+7y3）的值都是常数? 计算:3xy(x2y-xy2+xy)-xy2(2x2-3xy+2x)因式分解 已知:(x+2)2+|y+1|=0,求5xy2-{2x2y-[3xy2-(4xy2-2x2y)]}的值 试说明代数式(x3+3x2y-4xy2+6y3)-(2x3-x2y-xy2-y3-1)+(x34x2y+3xy2-7y3)的值与xy取值无关