x+y+z=1 x+3y+7z=-1 x+5y+8=2题错了 x+y+z=1 x+3y+7z=-1 x+5y+8z=2

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x+y+z=1x+3y+7z=-1x+5y+8=2题错了x+y+z=1x+3y+7z=-1x+5y+8z=2x+y+z=1x+3y+7z=-1x+5y+8=2题错了x+y+z=1x+3y+7z=-1x

x+y+z=1 x+3y+7z=-1 x+5y+8=2题错了 x+y+z=1 x+3y+7z=-1 x+5y+8z=2
x+y+z=1 x+3y+7z=-1 x+5y+8=2
题错了 x+y+z=1 x+3y+7z=-1 x+5y+8z=2

x+y+z=1 x+3y+7z=-1 x+5y+8=2题错了 x+y+z=1 x+3y+7z=-1 x+5y+8z=2
先将几个方程编个号：
x+y+z=1 (1)
x+3y+7z=-1 (2)
x+5y+8z=2 (3)
(3)-(1)得到：2y+6z=-2 (4)
(3)-(1)得到：4y+7z=1 (5)
将(4)式化简并移向得到y=-1-3z (6)
将(6)代入(5)得到4*(-1-3z)+7z=1,解得z=-1
将z=-1代入(5)得到y=2
再将z=-1和y=2代入(1)得到x=0
所以x=0,y=2,z=-1

已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 (1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=-1,Z+X=-1. x+y+z=6 x+2y+3z=14 y+1=z x+2y-z=1 3x-3y+z=2 3x+3y+z=7 {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 解方程：x+z=y (1) ,7z-(x+y)=2 (2) ,x+y+z=14 (3) {x+y+z=1 {x+3y+7z=2 {x+5y+19z=4 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 x：y：z=1：2：7 2x-y+3z=21 x：y：z=1：2：7 2x-y+3z=21 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 三元一次方程 X-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 X=?Y=?Z=? 解三元一次方程组 ①2x-y+z=1 3x+y -2z=2 X+2y-z=3 ②x-4y+z=-3 2x+Y-Z=18 X-Y-Z=7 ③4x+4y+2z=7 6X-4y-z=6 2x-y+z=1 {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1