解方程组:2x+y+z=-4 x+2y+z=-2 x+y+2z=3

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解方程组:2x+y+z=-4 x+2y+z=-2 x+y+2z=3
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解方程组:2x+y+z=-4 x+2y+z=-2 x+y+2z=3
解方程组:2x+y+z=-4 x+2y+z=-2 x+y+2z=3

解方程组:2x+y+z=-4 x+2y+z=-2 x+y+2z=3
2x+y+z=-4 (1)
x+2y+z=-2 (2)
x+y+2z=3 (3)
(1)+(2)+(3)
4x+4y+4z=-3
x+y+z=-3/4 (4)
(1)-(2),x=-13/4
(2)-(2),y=-5/4
(3)-(2),z=15/4

x=-13/4
y=-5/4
z=15/4

x=-13/4,y=-5/4,z=15/4

2x+y+z=-4
x+2y+z=-2
x+y+2z=3
2x+y+z=-4
2x+4y+2z=-4
x+y+2z=3
x-y=-2
x+3y=-7
4y=-5
y=-5/4
x=y-2=-13/4
z=-2-x-2y=-2-(-13/4)-2(-5/4)=15/4

(1)2x+y+z=-4 (2)x+2y+z=-2 (3)x+y+2z=3
(2)-(1)得:-x+y=2 (4)
(2)*2-(3)得:x+y=-7 (5)
(4)+(5)得:y=-5/4
把y=-5/4 代入(4)得:x=-13/4
把y=-5/4,x=-13/4代入(1)得:z=15/4 (完毕)

2x+y+z=-4 (1)
x+2y+z=-2 (2)
x+y+2z=3 (3)
(1)-(2)得出x-y=-2(40
(2)x2-(3)得出x+3y=-1(5)
(4)(5)连算得出y=-5/4
x=-13/4
z=15/4

(1)2x+y+z=-4
(2)x+2y+z=-2
(3)x+y+2z=3
第一道式子减第二道式子,得出y=x+2
第一道式子加第二道式子再减去第三道式子,得出2X+2Y=-9
则有2X+2(X+2)=-9
所以X=-13/4
再把X=-13/4代入方程y=x+2得出Y=-5/4
再将X=-13/4,Y=-5/4代放方程(1)
得出Z=15/4

一式乘以2减三式:3x+y=-11(四式)
二式乘以2减三式:x+3y=-7(五式)
四式乘以3减五式:8x=-26 所以x=-13/4带入五式:y=-5/4
把x,y带入一式:z=15/4

X=-13/4 Y=-5/4 Z=15/4