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

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 3x2y+xy2-[2xy2-4x2y+(x2y-2xy2)] 试说明:无论x,y取何值时,代数式(x3+3x2y-5+6y3)+(y3+2xy2+x2y-2x3)-(4x2y-x3-3xy2+7y2)的值是常数.要具体过程,注意格式 5xy2-【3xy2-(4xy2-2x2y)】+2x2y】+2x2y-xy2 化简,再求值 几道关于整式加减数学题,=1.3x+2xy-4y2-3xy=4y2-3x22.3x3-[x3+(6x2-7x)]-2(x3-3x2-4x)3.(3x2-4y2)+[-（x2-2xy-y2）]-[-(3x2-2xy-y2)]4.已知：(x=2)2+|y=1|=0,求5xy2-{2x2y-[3x2y-(4xy2-2x2y)]}的值5.如果A=3m2-m+1,B=2m2-m-7且A-B+C=0,求C以上 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? x3+x2y-xy2-y3= x3-2x2y+xy2-x 因式分解:x3-2x2y+xy2 -3x2y+2x2y+3xy2-2xy2 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 -3x2+2x2y+xy2 (4xy2-2x2y)-( )=x3-2x2y+4xy2+y3． (2x3-3x2y-2xy2)-(x3-2xy2+y3)+(-x3+3x2y-y3)当x=1/2,y=-1时,求值.当x=-1/2,y=-1时,求值. 若A=x3一2xy2+1,B=x3+xy2一3x2y,则2x3一7xy2+3x2y+3等于().A：3A一B,B：A+B,C：A一B,D：A一5B.请大家帮忙看看,这题该怎么选? (x2y)3 × (-xy2)3 分解因式:X3+2X2Y+2XY2+Y3= (X3-2x2y+xy2)÷（x3-xy2）要求约分