最后一道就可以了,x-y-z=-13x+5y+7z=114x-y+2z=-1
最后一道就可以了,x-y-z=-13x+5y+7z=114x-y+2z=-1
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
(x+y-z)(x-y+z)=
解方程组2x+y-z=7 x+y+z =1 2x-y-z=5
x/2=y/3=z/5 x+3y-z/x-3y+z
1.x+y+z=21,x-y=1,2x+z-y=13.2.3x+2y+z=13,x+y+2z=7 ,2z+3y-z=12
x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=?
X+Y+Z=?
一道数奥题,(x+y-z)²+(y+z-4)=-|z+x-5|
已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
解下列方程组(1)3x-y+z=3 2x+y-3z=11 x+y+z=12(2)5x-4y+4z=13 2x+7y-3z