x^2-y^2=xy 求x/y,

x^2+xy+x=36,y^2+xy+y=20,求x+y. 如果x^2+xy+y-14,y^@+xy+x=28,求x+y的值. 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+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/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理. 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!