4x^3y+4x^2y^2+xy^2

（-3x^y+2xy)-( )=4x^+xy x^2y+4xy+4y [-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y- 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值! xy=-2,x+y=3,求代数式（4xy+12y)+[7x-(3xy+4y-x)]