已知4x-3y-3z=x-3y+z=0(x、y、z不等于0)(1)求x:y:z (2)求2x+3y-4z/z的值
问题描述:
已知4x-3y-3z=x-3y+z=0(x、y、z不等于0)
(1)求x:y:z (2)求2x+3y-4z/z的值
答
(1)
4x-3y-3z=x-3y+z
3x=4z
x=4z/3
代入公式,得
x-3y+z=0
4z/3-3y+z=0
y=7z/9
∴ x:y:z=4/3:7/9:1=12:7:9
(2)PS:你应该少打了括号
(2x+3y-4z)/z=(2*4z/3+3*7z/9-4z)/z
=(8z/3+7z/3-4z)/z
=(15z/3-4z)/z
=(5z-4z)/z
=z/z
=1
答
4x-3y-3z=x-3y+z=0
4x/z-3y/z-3=0.①
x/z-3y/z+1=0.②
①-②得:3x/z-4=0
x/z=4/3代入②得:4/3+1-3y/z=0
y/z=7/9
x:y=(4/3)/(7/9)=4:(7/3)=12:7
x:z=12:9
x:y:z=12:9:7
2)
(2x+3y-4z)/z=2x/z+3y/z-4
=8/3+7/3-4
=5-4
=1