已知2x=3,2y=5,2z=15.求证x+y=z
已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3
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^2+y^2+z^2=1,求证x+y+z-2xyz
已知三个实数x,y,z满足条件(z-x)^2-4(x-y)(y-z)=0,求证:x,y,z成等差数列
已知2x次方=3 2y次方=5 2z次方=15,求证:x+y+z
已知3x+4y+5z=1求证X^2+y^2+z^2大于等于1/50
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
x/2=y/3=z/5 x+3y-z/x-3y+z
已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=?
已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z
已知x:y:z=3:4:5,3x+2y-4z=18.求:x+y+z.
已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值