1、x+y+z=2(1)
3x-y-4z=5(2)
2x+3y-2z=0(3)
(1)+(2)得
4x-3z=7(4)
(1)*3-(3)得
x+5z=6
x=6-5z
将上式代入(4)得
4(6-5z)-3z=7
24-20z-3z=7
23z=17
z=17/23
x=53/23
y=-24/23
2、2x+3y+z=38(1)
3x+4y+2z=56(2)
4x+5y+z=66(3)
(1)*2-(3)得
x+2y=20(4)
(3)*2-(2)得
5x+6y=76(5)
(5)-(4)*3得
2x=16
x=8
y=6
z=4
谢谢哦,我还有一道不会,你能教我吗也是解三元一次方程组题目是x/2=y/3=z/5,2x+y+3z=88
设x/2=y/3=z/5=kx=2ky=3kz=5k2x+y+3z=882*2k+3k+3*5k=8822k=88k=4x=8y=12z=20