-1/6x^2y^m+1+xy^2-3x^3-6是6次4项和单项式3.6x^2ny^5-m次数一样,求m、n

1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 1 x²y-3xy²2 2x(2x-y)+y(y-2x)3 -6x(m-2n)+12(2n-m)4 3(y-x)²-(x-y)³5 4a²-366 (x-2y)²-x²7 4x³y+4x²y²+xy³8 (x+y)²-2m(x+y)+m²9 x²-9x+1810 -8x²-10x-3 计算3xy[2xy-x(y-2)+x-1] 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 关于x、y代数式x^2-(3m-3)xy+5y-6xy^3-（1/3n+1)y^3+3x不含xy和y^3项,求3m-2n的值. 若多项式5x*x-2mxy-3y*y+4xy-3x+1中不含xy项,求（-（m*m*m）+2（m*m）-m+1）-（m*m*m+2m*m-m+4） 化简求值x-4y/2x-7xy+3y×x-2xy-3y/2x+3xy-2y÷3x-6y/4x-4xy+y,其中：x=1999,y=-1 在方程组(1)X+Y=M (2)2X-Y=6 若XY 关于x,y得多项式（5m+1)x^2y+(4n-2)xy^2-3x+y-(-2m-6)x^2y+(3-3n)xy^2 不含三次项,求5m+2n的值关于x,y的多项式（5m+1)x^2y+(4n-2)xy^2-3x+y-(-2m-6)x^2y+(3-3n)xy^2 不含三次项,求5m+2n的值 把下列多项式分解因式(1).xy+x+y+1(2)x²+x-y²+y（3)1-m²-n²+2mn（4）x²-4xy+4y²-3x+6y 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 已知多项式-6xy-7x^3m-1y^2+3分之4x^3y-x^2y-5是七次多项式,求m的值? 因式分解x^2y^2+x^2y+xy^2+3xy+x+y+1 -3(2x-xy)-4(-6+xy+x.其中x=1,y=-1 已知x-y=6,xy=-1,求(2x+3x-2xy)-(x+4y+xy)-(3yx-2x+2y)的值 .(x+y-2)(x+y-2xy)+(xy-1)^2 xy(xy+1)+xy+3-2(x+y+1/2)-(x+y-1)^2因式分解