已知 x-3y=0 求(2x+y)/(x²-2xy+y²)*(x-y)

问题描述:

已知 x-3y=0 求(2x+y)/(x²-2xy+y²)*(x-y)
有分……

x-3y=0
x=3y
(2x+y)/(x²-2xy+y²)*(x-y)
=(2x+y)/(x-y)
=(7y)/(2y)
=7/2