已知x+y/x=11/8,求x-y/x+2y的值

问题描述:

已知x+y/x=11/8,求x-y/x+2y的值

(x+y)/x=11/8
8x+8y=11y
8x=3y
y=8x/3
(x-y)/(x+2y)
=(x-8x/3)/(x+16x/3)
=(-5x/3)/(19x/3)
=-5/19