已知x:y:z=1:2:3,且x+y+z=66,(3x^2y^2+8x^2z^2-12y^2z^2)/(xyz)的值
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
已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值
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属于R+(正实数),且xyz(x+y+z)=4+2*根号下3,则(x+y)(y+z)的最小值是?
已知xyz不等于0,且x+2y-z=0,7x-y-z=0,求x+y+z/2x-y-z的值.
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
设X+Y+Z=0求X^3+X^2Z-XYZ+Y^2Z+Y^3的值
已知x+y-7z=0 x-2y+5z=0(xyz不等于0),求x+2y-z/y-2x+12z
已知x+y/2=y+z/3=z+x/4,且x+2y+z=12,求x-2y+z的值
已知2X+5Y+4Z=0,3X+Y-7Z=0,且XYZ不等于0,求(X+Y+Z)/(2X-3Y+4Z)的值
已知实数xyz满足x/y+z+y/z+x+z/x+y=1求x^2/y+z+y^2/z+x+z^2/x+y的值