-1/2(4xy-8x^2y^2)+1/3(xy-6x^2y^2)化简,谢谢

(x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 1-2/x+y=xy,4y+6x=xy.求xy的解? .(x+y-2)(x+y-2xy)+(xy-1)^2 7x^2y-[xy+4(xy^2+1/8xy)-3x^2y]答对给分 因式分解xy(xy+2)+6(xy+8)-4(x+y-2)^2-16(x+y+1)谢谢 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 x-2xy-1+4y² (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 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x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 计算：（1）8x^2y^2*(-3x/4y^5) (2)(x+y)^2/xy-y^2*(y-x)^2/xy+y^2 联立方程 x^2-xy-2y^2=8(1) xy+y^2=4(2) 分解因式（x^2+3x+2)(3+8x+4x^2)-90xy(xy+1)+(xy+3)-2(x+y+0.5)-(x+y-1)^2 若（x+1)^2+|y-2|=0,求3x^2-[5xy-(x^2y-3xy)+4x^2y-8xy]的值 x-y/x^2+xy除以xy-x^2/x^2y^2-x^4*1/x-y