x+y=5,y+z=-1,z+x=-2怎么算
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
(x+y-z)(x-y+z)=
x/2=y/3=z/5 x+3y-z/x-3y+z
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
语句{intx,y,z ;x=1,y=z=2; ++x&&y--||++z}怎么理解
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
3元1次方程怎么算第一题:2x+y+z=10 x+2y+z=-6 x+y+2z=8 第2题 :5x+4y-3z=13 2
x+2y+z=1 x+y+2z=2 2x+y+z=5
解方程组2x+y-z=7 x+y+z =1 2x-y-z=5
3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5
x+y+z=2 x-3y+2z=1 2x+2y+z+5 要具体步骤..
(x*x+y*y+z*z)-(X+Y+Z)=?excel公式怎么表达