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已知三元一次方程组13x+5y+9z=18.5,4x+2y+3z=6.2,6x+5y+2z=8的解为x=0.5,y=0.

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/25 11:41:07
已知三元一次方程组13x+5y+9z=18.5,4x+2y+3z=6.2,6x+5y+2z=8的解为x=0.5,y=0.6,z=1,求
13x+5y+9z=18.5················①
4x+2y+3z=6.2···················②
6x+5y+2z=8····················③
①-③得
7x+7z=10.5·····················④
②×5-③×2得
8x+11z=15················⑤
联立④⑤解得
x=0.5,z=1
把x=0.5,z=1代入②得
y=(6.2-4×0.5-3×1)/2=(6.2-2-3)/2=0.6
所以方程组的解为x=0.5,y=0.6,z=1
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