X+3Y-Z=13 (1) 3X-2Y-Z=2 (2) 2X-Y+Z=-3 (3)
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X+3Y-Z=13 (1) 3X-2Y-Z=2 (2) 2X-Y+Z=-3 (3)
X+3Y-Z=13 ①
3X-2Y-Z=2 ②
2X-Y+Z=-3 ③
②+③,得5x-3y=-1 ④
①+③,得3x+2y=10 ⑤
④×2,得10x-6y=-2 ⑥
⑤×3,得9x+6y=30 ⑦
⑥+⑦,得19x=28,∴x=28/19
把x=28/19代入④,得(140/19)-3y=-1,y=53/19
把x=28/19,y=53/19代入①,得
(28/19)+(159/19)-z=13,z=-60/19
∴原方程组的解是{x=28/19
y=53/19
z=-60/19
3X-2Y-Z=2 ②
2X-Y+Z=-3 ③
②+③,得5x-3y=-1 ④
①+③,得3x+2y=10 ⑤
④×2,得10x-6y=-2 ⑥
⑤×3,得9x+6y=30 ⑦
⑥+⑦,得19x=28,∴x=28/19
把x=28/19代入④,得(140/19)-3y=-1,y=53/19
把x=28/19,y=53/19代入①,得
(28/19)+(159/19)-z=13,z=-60/19
∴原方程组的解是{x=28/19
y=53/19
z=-60/19
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