(4x-2y-1)^2+√xy-2=0,求4x^2y-4x^2y2+xy^2的值

1-2/x+y=xy,4y+6x=xy.求xy的解? 已知/X-Y-1/+(XY+3)的平方=0,求(-2XY+2X+3Y)-(3XY+2Y-2X)-(X+4Y+XY)的值!已知/X-Y-1/+(XY+3)的平方=0,求(-2XY+2X+3Y)-(3XY+2Y-2X)-(X+4Y+XY)的值急! 下面都是求微分方程的通解：1、(y^-2xy)dx+x^2dy=0 2、(x^2+y^2)dy/dx=2xy 3、xy’-y=xtan(x/y)4、xy’-y=(x+y)ln[(x+y)/x] 5、xy’=√(x^2-y^2) +y新手求学,请大哥大姐们指点下~ 已知x^2+y^2+x^2y^2-4xy+1=0 求(x-y)^2008-(xy)^2008 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 (-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 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 若（x+1)^2+|y-2|=0,求3x^2-[5xy-(x^2y-3xy)+4x^2y-8xy]的值 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 已知|3-y|＋|x+y|=0,求[2(x+y)-3(xy+4)]÷1／xy的值. 已知（x+2)^2+|y+1|=0,求5xy^2-{2x^2y-[3xy^2-(4xy^2-2x^2y)]} （-3x^y+2xy)-( )=4x^+xy 已知（x+2）*+|y+1|=0求5xy*-｛2x*y-【3xy*-（4xy*-2x*y）】｝的值