现有一道题,已知x/2=y/3=z/4,求分式(x+2y-z)/(x+y-3z)
问题描述：
现有一道题,已知x/2=y/3=z/4,求分式(x+2y-z)/(x+y-3z)
答
x/2=y/3=z/4
x=2y/3=2z/4
4y/3=z
(2y/3+2y-4y/3)/(2y/3+y-4y)
=(2/3+2-4/3)/(2/3+1-4)
=(2+6-4)/(2+3-12)
=-4/7