几道预初数学题,
1.2x=3y=6z
x+2y+z=16
2.a+2b=2
2b+3c=4
3c+a=6
3.a-b=2 a-c=1/2,则（b-c）³-（b-c）+9/4 等于?
4.x+2y=3
x-2y=1
2x+3y+z=6.5
5.x:y=4:7
x:z=3:5
x-2y+3z=30
6.x/3=y/4=z/5
x-2y+3z=30