[5xy^2(x^2-3xy)-(-3x^2y^2)^3]/5x^2y^2 计算.

计算：(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3 计算3xy[2xy-x(y-2)+x-1] 计算：3xy[2xy-x（y-2）+x] (3x-y)^2+(2x+3y)(-2x-3y)+5xy 计算 （x^2+xy/x-y)/（xy/x-y)计算 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 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-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) [5xy^2(x^2-3xy)-(-3x^2y^2)^3]/5x^2y^2 计算. 计算：(5xy^2(x^2-3xy)-(-3x^2y)^2)/2x^2y^2 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 已知xy/x+y=3,求代数式2x-5xy+2y/x-3xy+y