x^2+xy-2y^2=0,求3x-y/x+y的值

已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 已知y-x-2xy=0,求3x+xy-3y/y-xy-x的值 已知y-x-2xy=0,求(3x+xy-3y)\(y-xy-x)的值 已知x-3y=0,求（2x+y)/(x^2-2xy+y^2)*(x-y)的值 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值. 已知x-3y=0,求(2x+y)(x-y)/x^2-2xy+y^2的值 已知x-3y=0,求2x+y/x-2xy+y乘(x-y)的值 已知x^2+y^2+xy-3y+3=0,求y^x的值 已知2x^2-3xy+y^2=0,xy不等于零,求x/y+y/x的值 已知x^2-xy+3y^2=0 且xy不等于0 求x/y+y/x 的值