x^2-2xy+y^2+2xy-2xy+3

（xy-x^2)乘以(xy)/(x-y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) x^2-xy-6y^2+3xy+y+2 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-1] 计算：3xy[2xy-x（y-2）+x] （-3x^y+2xy)-( )=4x^+xy 因式分解：(2x-y)(x^2+xy-2y^2) xy(x^2-xy)(-3xy^2) 3xy-3xy-xy+2yx x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?