3x+2y+z=9 x-3y-2z=1 -x+4y=5
问题描述：
3x+2y+z=9 x-3y-2z=1 -x+4y=5
答
由1式得：6x+4y+2Z=18
1加2 7x+y=19
然后加x=4y-5带入上式得 y=54/29，x=71/29.Z=-60/29
答
3x+2y+z=9 (1)
x-3y-2z=1 (2)
-x+4y=5 (3)
2(1)+(2)
7x+y = 19 (4)
4(4) -(3)
29x=71
x=71/29
from (3)
y = 54/29
from (1)
3x+2y+z=9
3(71/29)+2(54/29)+z=9
z =-60/29