已知x-3y=0,求(x^2-2xy+y^2分之2x+y)×(x-y)的值?
问题描述：
已知x-3y=0,求(x^2-2xy+y^2分之2x+y)×(x-y)的值?
答
x-3y=0
x=3y
(x^2-2xy+y^2分之2x+y)×(x-y)
=(2x+y)/(x-y)^2*(x-y)
=(2x+y)/(x-y)
=(6y+y)/(3y-y)
=7y/2y
=7/2