证明2X-3Y-1是4X^2-4XY-3Y^2+4X-10Y-3的一个因式

试证明(x^3+3x^2y-2xy^2+1)+(x^3-4x^2y+3xy^2-10)+(-xy^2+x^2y-2x^3+3)的值与x,y无关 证明：代数式[(x+y)(x-y)-(x+y)^2-2y(x-y)-2xy]/xy 的值为x,y的值无关 解方程 (x+1)^5/(-1-x)^4=3x+7一定要100%正确阿. 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 证明2X-3Y-1是4X^2-4XY-3Y^2+4X-10Y-3的一个因式 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 分解因式x^2y+x^2y+2xy^2-4xy^3是x^3y+x^2y+2xy^2-4xy^3 已知1/x - 1/y = 2,求3x+7xy-3y / 2x-3xy-2y的值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)=-1/71/x-1/y=2到(y-x)/xy=2 是怎么变化的.. 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² （-3x^y+2xy)-( )=4x^+xy 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 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 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