x-y-5z=4,2x+y-3z=10,3x+y+z=8解方程组

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x-y-5z=4,2x+y-3z=10,3x+y+z=8解方程组

x-y-5z=4,2x+y-3z=10,3x+y+z=8解方程组
x-y-5z=4,2x+y-3z=10,3x+y+z=8解方程组

x-y-5z=4,2x+y-3z=10,3x+y+z=8解方程组
先观察,发现只有y前系数为1或-1,所以,两两组成方程组,再把y消掉.
分别把如下定义为1式、2式、3式：
x-y-5z=4,2x+y-3z=10,3x+y+z=8
由1式和2式消去y得4式:3x-8z=14
由1式和3式消去y得5式:4x-4z=12/x-z=3
5式乘以3再减去4式得：5z=-5,即z=-1
把z=-1代入5式得x=2
把z=-1,x=2代入1式得：y=3

2x-2y-10z=8,2x+y-3z=10,所以3y+7z=2
3x-3y-15z=12,3x+y+z=8,所以4y+16z=-4
由此解出y和z，进而求出x

x=2 y=3 z=-1

(4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 2x+z=10 x+y-z=4 3x-y-z=0 x+y+2z=5 2x-y-z=4 3x+y-3z=10 {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 -2X+3Y+Z=-4-X-5Y-2Z=-13X+Y-Z=10 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 三元一次方程组,1.x-2y+z=9 2x+y+3z=10 3x+2y1.x-2y+z=92x+y+3z=103x+2y-z2.3x-5y+2z=14x+5y-z=5X-5y+3z=-23.7x+2y-z=76x-y+z=74x+3y+z=94.4x+3y-2z=-75x-6y+z=12x+z=-25.2x+3y-4z=-23x-2y+5z=262x+5z=31 方程组{x/2+y/3-z=-5,x/3-y/2+z/2=10,x/2-y/3-z/4=6,求x,y,z x+y-2z=5 2x-y-z=4 3x+y-3z=10；分别求x、y、z的值. 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z x-y-2z=10 y-3z=-4 3x-y+5Z=21 三元一次方求大神x-y-2z=10y-3z=-43x-y+5Z=21 x+2y+3z=23 y-z=5 x+2z=10 x/2=y/3=z/5 x+3y-z/x-3y+z x+y/2=z+x/3=y+z/4 x+y+z=27 6x-y-z=3 2x-4y+8z=5 3x-6y-z=10 y z 分别等于几?大虾 x+2y=3x+2z=4y+z 求x:y:z 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值