4x-3y-z=16,2x+2y+3z=8,x+4y+5z=3
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4x-3y-z=16,2x+2y+3z=8,x+4y+5z=3
4x-3y-z=16.(1)
2x+2y+3z=8.(2)
x+4y+5z=3 .(3)
(2)*2-(1):4x+4y+6z-(4x-3y-z)=16-16
7y+7z=0...(4)
(3)*4-(1):4x+16y+20z-(4x-3y-z)=12-16
19y+21z=-4.(5)
(4)*3-(5):21y+21z-(19y+21z)=0+4
2y=4
y=2
把y=2代入(4)
有z=-2
将y=2,z=-2代入(3)中,有
x+8-10=3
x=5
所以x=5,y=2,z=-2
2x+2y+3z=8.(2)
x+4y+5z=3 .(3)
(2)*2-(1):4x+4y+6z-(4x-3y-z)=16-16
7y+7z=0...(4)
(3)*4-(1):4x+16y+20z-(4x-3y-z)=12-16
19y+21z=-4.(5)
(4)*3-(5):21y+21z-(19y+21z)=0+4
2y=4
y=2
把y=2代入(4)
有z=-2
将y=2,z=-2代入(3)中,有
x+8-10=3
x=5
所以x=5,y=2,z=-2
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
x/2=y/3=z/5 x+3y-z/x-3y+z
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
1.x+y=16,y+z=12,z+x=102.3x-y+z=4,2x+3y-z=12,x+y+z=63.x+y+z=6
已知x:y:z=3:4:5,3x+2y-4z=18.求:x+y+z.
{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
2x+5y+4z=6,3x+y-7z=-4,x+y-z=?
x/3=y/4=z/5,求x+y+z/3x-2y+z的值,
若x/3=y/4=z/5,求x+y+z/3x-2y+z的值.
已知2x+5y+4z=6 3x+y-7z=-4求x+y-z
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?