x^2-3xy+y^2/2x^2--3xy+5y^2

(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 x^2-xy-6y^2+3xy+y+2 5x^2y/-1/2xy*3xy^2 （xy-x^2)乘以(xy)/(x-y) 5xy^2-[3xy^2-(4xy^2-2x^y)]+x^2y-xy^2如何化简 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 2x平方y-2xy+3xy平方+5+2xy+x平方y-3xy平方-3 过程! 计算3xy[2xy-x(y-2)+x-1] 计算：3xy[2xy-x（y-2）+x] 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