-x^3+x^2y-1/4xy^2(m+n)^2-4(m+n-1) (a^2+b^2)^2=4a^2b^2 16x^4-72^2+81 (x^2-2x)^2+2(x^2-2x)+1

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） XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 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 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² 关于xy的方程组3x+2y=m+1,4x+y=m,的解满足x ,y均小于2,求m的值 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 （1）.x^2-xy+x (2).m^2n-mn^2+mn (3).9x^3y^3-21x^3y^2+12x^2y^2 (4).x^2(x-y)+y^2(x-y)多项式因式分解 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 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 已知多项式2x+xy-3y-x-4y-1可以分解为（2x+3y+m）（x-y+n）,