(-2x^2y)^3+6(x^2)^2*(-x)^2*(-y)^3-3x^3(-xy)^3=

(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy (x+y)(x-y)-(2xy+3y)平方 已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy （-3x^y+2xy)-( )=4x^+xy x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 化简分式方程:x*x-xy-y*y/x*x-3x-6y+2xy 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}