①3x-4y+z=14x+5y+2z=172x+2y-z=3② x:y=3:2y:z=5:4x+y+z=66

1)
①+③:5x-2y=17 ④
②+2*③:5x+9y=23 ⑤
⑤-④:11y=6,得y=6/11
故x=(2y+17)/5=(12/11+17)/5=199/55
代入③：z=2x+2y-3=398/55+12/11-3=293/55
2) 令x=3t,y=2t,则z=4y/5=8t/5
代入③：3t+2t+8t/5=66
33t/5=66
t=10
故x=30,y=20,z=16