解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1 哪怕写一题也好啊
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![解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1 哪怕写一题也好啊](/uploads/image/z/469137-57-7.jpg?t=%E8%A7%A3%E4%B8%8B%E5%88%97%E6%96%B9%E7%A8%8B%E7%BB%84%EF%BC%9A%281%29x%2B2y%3D9+y-3z%3D-5+5z-x%3D14+%282%29x%3Ay%3D3%3A2+y%3Az%3D5%3A4+x%2By%2Bz%3D66+%283%292x-2y%2Bz%3D0+2x%2By-z%3D1+x%2B3y-2z%3D1%E8%A7%A3%E4%B8%8B%E5%88%97%E6%96%B9%E7%A8%8B%E7%BB%84%EF%BC%9A%281%29x%2B2y%3D9+y-3z%3D-5+5z-x%3D14+%282%29x%3Ay%3D3%3A2+y%3Az%3D5%3A4+x%2By%2Bz%3D66+%283%292x-2y%2Bz%3D0+2x%2By-z%3D1+x%2B3y-2z%3D1+%E5%93%AA%E6%80%95%E5%86%99%E4%B8%80%E9%A2%98%E4%B9%9F%E5%A5%BD%E5%95%8A)
解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1 哪怕写一题也好啊
解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1
解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1 哪怕写一题也好啊
解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1解下列方程组:(1)x+2y=9 y-3z=-5 5z-x=14 (2)x:y=3:2 y:z=5:4 x+y+z=66 (3)2x-2y+z=0 2x+y-z=1 x+3y-2z=1 哪怕写一题也好啊
(1)x+2y=9① y-3z=-5② 5z-x=14③
①+③得:2y+5z=23④
④-②×2得:11z=33,z=3;代入②得:y=4;代入③得:x=1.
(2)x:y=3:2① y:z=5:4② x+y+z=66③
x∶y=3∶2=(3×2.5)∶(2×2.5)=7.5∶5
所以x∶y∶z=7.5∶5∶4
x=66×7.5÷(7.5+5+4)=45
y=66×5÷(7.5+5+4)=20
z=66×4÷(7.5+5+4)=16.
(3)2x-2y+z=0① 2x+y-z=1② x+3y-2z=1③
①+②得:4x-y=1④
①×2+③得:5x-y=1⑤
⑤-④得:x=0,把x=0代入⑤得:y=-1
把x=0、y=-1代入①得:z=-2
(1)
x+2y=9 y-3z=-5 5z-x=14
y-3z=-5→y=3z-5→2y=6z-10→x+6z-10=9→x+6z=19→11z=33→z=3→x=1→y=4
(1)x=1,y=4,z=3
(2)x=30,y=20,z=16
(3)x=-2,y=-1,z=2