x-y+z=5 2x+3y+z=-2 x-2y-z=3
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x-y+z=5 2x+3y+z=-2 x-2y-z=3
![x-y+z=5 2x+3y+z=-2 x-2y-z=3](/uploads/image/z/19835640-0-0.jpg?t=x-y%2Bz%3D5+2x%2B3y%2Bz%3D-2+x-2y-z%3D3)
x-y+z=5 (1)
2x+3y+z=-2 ( 2)
x-2y-z=3(3)
由(1)得 z =5+y- x(4)
把(4)代入( 2)中得 2x+3y+5+y- x=-2
x+4y+5=-2 (5)
把(4)代入( 3)中得x-2y-(5+y- x)=3
2x-3y-5=3 (6)
由(5)(6)得
x=1 y=-2
把x=1 y=-2代入(1)得
1-(-2)+z=5
z=2
∴x=1
y=-2
z=2
2x+3y+z=-2 ( 2)
x-2y-z=3(3)
由(1)得 z =5+y- x(4)
把(4)代入( 2)中得 2x+3y+5+y- x=-2
x+4y+5=-2 (5)
把(4)代入( 3)中得x-2y-(5+y- x)=3
2x-3y-5=3 (6)
由(5)(6)得
x=1 y=-2
把x=1 y=-2代入(1)得
1-(-2)+z=5
z=2
∴x=1
y=-2
z=2
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