已知x^2-5XY+4y^2=0求分式x-y/x+y的值⊙﹏⊙b汗.

问题描述:

已知x^2-5XY+4y^2=0求分式x-y/x+y的值⊙﹏⊙b汗.

x²-5xy+4y²=0
(x-4y)(x-y)=0
即:x-4y=0得:x=4y或者:x-y=0得:x=y
则:(x-y)(x+y)
1、若x=y,则这个值是0
2、若x=4y,则=(4y-y)/(4y+y)=3/5