因为x/2=y/3=z/4≠0,所以y=(3/2)x z=2x
代入
x-y-z / 3x+2y-z = (x-(3/2)x -2x )/(3x+2(3/2)x - 2x )
(简化+分式上下同时乘以2)
=(2x-7x)/8x
约分=-5/8
x/2=y/3=z/4=a≠0 x=2a y=3a z=4a
2a-3a-4a/6a+6a-4a=-5a/8a=-5/8
由题 可设 x/2=y/3=z/4=R ≠0 ,
则 x=2R,y=3R,z=4R,
所以
(x-y-z) / (3x+2y-z)
=(2R-3R-4R) / (3*2R+2*3R-4R)
=(-5R) / (8R)
=-5/8