已知:x+y+z=0,求证:x³+y³+z=3xyz.
已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz
已知x,y,z满足xyz=1,求证x^3/(x+y)+y^3/(y+z)+z^3/(z+x)大于等于3
已知xyz属于R+,x+y+z=1,求证x^3/(y(1-y))+y^3/(z(1-z))+z^3/(x(1-x))大于
已知x,y,z都是正数,且xyz=1,求证:x^2/(y+z)+y^2/(x+z)+z^2/(x+y)≥3/2
已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)
已知:(x+y)/z=(x+z)/y=(z+y)/x,且xyz不等于0,则分式(x+y)(x+z)(z+x)/xyz的值
已知x^2+y^2+z^2=1,求证x+y+z-2xyz
已知X,Y,Z为3个互不相等的实数,且X+1/Y=Y+1/Z=Z+1/Z求证(xyz)^2=1
已知x+y+z=0,xyz=1,求证:x,y,z中必有一个大于2/3.
求教初二数学难题已知:(1/x+1/y+1/z)^(1/3)=1/x+1/y+1/z,且xyz>0,求证:1/x+1/y
已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少
已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值