.化简(x-2xy)^2乘x-(9xy^3-12x^4y^2)除3xy-(2xy)^2乖x其中x=2.y=1
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.
先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1
计算:3xy[2xy-x(y-2)+x]
化简!1、(x^2-xy)+xy+y^2 2、3(x^2-xy)-xy+y^2
(-3x^y+2xy)-( )=4x^+xy
-3(2x-xy)-4(-6+xy+x.其中x=1,y=-1
已知x-y=4,xy=-2,求代数式(2x+3y-2xy)-(x+4+xy)-(3xy+2y-2x)的值
已知x+xy=-2,xy-y=-6求代数式2x{-4y-3[(x+xy)²+x]-½[(y-xy
(x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
2xy-1/2(4xy-8x²y²)+2(3xy-5x²y²),其中x=3/2,