已知x=3y,求2x+y/x05-2xy+y05×(x-y)的值已知x-3y=0,求（2x+y）/（x2-2xy+y2）×(x-y)的值

Question

已知x=3y,求2x+y/x05-2xy+y05×(x-y)的值
已知x-3y=0,求【（2x+y）/（x2-2xy+y2）】×(x-y)的值

Answer 1

[(2x+y)/(x²-2xy+y²)]·(x-y)
=[(2x+y)/(x-y)²]·(x-y)
代入x=3y
原式=(7y/4y²)·2y
=(7/4y)·2y
= 7/2