3x^2 y+{xy-[3x^2 y-(4xy^2 +1/2xy)]-(4x^2 y+3/2xy)}

（-3x^y+2xy)-( )=4x^+xy 先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) 计算3xy[2xy-x(y-2)+x-1] 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 已知：x-y=1,xy=-2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 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 5xy^2-[3xy^2-(4xy^2-2x^y)]+x^2y-xy^2如何化简 xy(xy+1)+(xy+3)-2(x+y+2分之一）-(x+y-1)的平方