若x/2=y/3=z/4 则2x+3y/z 等于?
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
若x比y比Z=2比5比7 则 2x+2y+z分之3x+4y-2z等于?
若3x+5y+6z=5,4x+2y+z=2,则x+y+z的值等于【】
若3x+5y+6z=5,4x+2y+z=2,则x+y+z的值等于( )
若2x+5y+4z=0,3x+y-7z=0,则x+y-z的值等于( )
4x-3y-6z=0,x+2y-7z=0是一个方程组,那么x-y+z/x+y+z的值等于
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
若x-2y+4z=1,x+3y-7z=0,则y:z=?
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
已知x+y=3,y+z=4,x+z=5,则x+y+z等于( )
y=-2X,Z=3y,那么X-Y+(-Z)等于
若2x+5y+4z=6,3x+y-7y=-4,则x+y-z等于多少