{2x+3y-4z=-5 x+y+z=6 x-y+3z=10

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{2x+3y-4z=-5 x+y+z=6 x-y+3z=10

{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
{2x+3y-4z=-5 x+y+z=6 x-y+3z=10

{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
(1)2x+3y-4z=-5
(2) x+y+z=6(两边同时×3
3x+3y+3z=18(与(1)相减得(5)
(3)x-y+3z=10(与(2)相加得(4))
(4)2x+4z=16
(5)x+7z=23(两边同时×2,然后与(4)相减)
2x+14z=46
10z=30
z=3(代入到(5)
x=23-7*3=2
把x=2;z=3代入到(2)
y=6-2-3=1
所以:
x=2
y=1
z=3

x=2
y=1
z=3
具体步骤是把二式与三式相加,得x+2z=8,相减得z-y=2,可得x=8-2z,z=y+2,x=4-2y,
把z与y的关系式,x与y的关系式代入2x+3y-4z=-5中,得y=1,则z=3,x=2
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