化简此式,(x^2-4xy)/(x^2-4xy+4y^2)

5xy^2-[3xy^2-(4xy^2-2x^y)]+x^2y-xy^2如何化简 （-3x^y+2xy)-( )=4x^+xy 化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1, x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y x^2y+4xy+4y (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 计算:4xy-(x+y)^2/xy(x+y)(x-y)÷x^2+xy-2y^2/x^2y+2xy^2 先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1 -3(xy-2x²)-[y²-(5xy-4x²)+2xy] 化简求值3x-2y-5xy-（2x-3y+2xy）,其中x+y=4,xy=-7 （3x-2y+3xy）-（x-4y-2xy）,其中x+y=3 xy=-2 化简求值