化简求值1.x^2+2xy+y^2/x^2-y^2除以x^2+xy/xy-y^2X=1Y=-2011
化简求值1.x^2+2xy+y^2/x^2-y^2除以x^2+xy/xy-y^2X=1Y=-2011
化简求值:[x(xy-1)^2-(xy+2)(2-xy)]除以4分之1xy,其中x=-2,y=5分之1.
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1
①化简求值:2(x^2y+xy)-3(x^2y-xy)-4x^2y,其中x=1,y=-1.
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.
化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1,
化简求值:x-y/x²-2xy+y²-xy+y²/x²-y²,其中(x
化简求值:(-1/3XY)²[xy(2x-y)-2x(xy-y²)],其中X=-3/2,Y=-2
化简求值:(1)已知x+y=6,xy=-2,求(x^4-y^4)÷(x^2+y^2/xy)÷(6x-6y);
化简求值:2(x的平方y+xy)-3(x平方y+xy)-4x平方y,其中x=-1,y=2
化简求值y/x-y +y立方/x立方-2x平方y+xy平方除以xy+y平方/y平方-x平方,其中x=2/3,y=-3
先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1