求方程组 x+y+z=15000 (1/50)x+(1/20)y+(1/10)z=720 x=2z 的解 求简单过程求方程组 x+y+z=15000(1/50)x+(1/20)y+(1/10)z=720x=2z 的解 求简单过程
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/04 22:13:20
![求方程组 x+y+z=15000 (1/50)x+(1/20)y+(1/10)z=720 x=2z 的解 求简单过程求方程组 x+y+z=15000(1/50)x+(1/20)y+(1/10)z=720x=2z 的解 求简单过程](/uploads/image/z/5246302-22-2.jpg?t=%E6%B1%82%E6%96%B9%E7%A8%8B%E7%BB%84+x%2By%2Bz%3D15000+%26%238203%3B%EF%BC%881%2F50%EF%BC%89x%2B%281%2F20%29y%2B%281%2F10%29z%3D720+x%3D2z+%E7%9A%84%E8%A7%A3+%E6%B1%82%E7%AE%80%E5%8D%95%E8%BF%87%E7%A8%8B%E6%B1%82%E6%96%B9%E7%A8%8B%E7%BB%84+x%2By%2Bz%3D15000%EF%BC%881%2F50%EF%BC%89x%2B%281%2F20%29y%2B%281%2F10%29z%3D720x%3D2z+%E7%9A%84%E8%A7%A3+%E6%B1%82%E7%AE%80%E5%8D%95%E8%BF%87%E7%A8%8B)
求方程组 x+y+z=15000 (1/50)x+(1/20)y+(1/10)z=720 x=2z 的解 求简单过程求方程组 x+y+z=15000(1/50)x+(1/20)y+(1/10)z=720x=2z 的解 求简单过程
求方程组 x+y+z=15000 (1/50)x+(1/20)y+(1/10)z=720 x=2z 的解 求简单过程
求方程组
x+y+z=15000
(1/50)x+(1/20)y+(1/10)z=720
x=2z
的解 求简单过程
求方程组 x+y+z=15000 (1/50)x+(1/20)y+(1/10)z=720 x=2z 的解 求简单过程求方程组 x+y+z=15000(1/50)x+(1/20)y+(1/10)z=720x=2z 的解 求简单过程
把x=2z
带入(1)(2)
y+3z=15000 (3)
1/25y+1/20y+1/10z=720
(3)变形为y=15000-3z 代入上式
得y = 66000/17,z = 63000/17
x=2z=126000/17
将3代入1和2,
3z+y=15000,
z/25+y/20+z/10=720;7z/50+y/20=720,14z+5y=7200
解得:z=67800,x=135600,y=-188400