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
答
4/7
答
(x+y)/x=11/8
11x=8(x+y)
3x=8y
x=8y/3
(x-y)/(x+2y)
=(8y/3-y)/(8y/3+y)
=(5/3)/(11/3)
=5/11
答
(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