若y-2x=0,则分式(x^2+xy+y^2)/(x^2-xy+2y^2)=

问题描述:

若y-2x=0,则分式(x^2+xy+y^2)/(x^2-xy+2y^2)=

y-2x=0,y=2x
(x^2+xy+y^2)/(x^2-xy+2y^2)
=(x^2+3x^2+4x^2)/(x^2-3x^2+4x^2)
=7x^2/2x^2
=7/2