若2x+5y-4z=0.3x+9y-7z=0,则x+y-z的值为------------------
若4x=7y+5z,2x+y=z,则x:y:z的值为
若2x+5y-4z=0,3x+9y-7z=0,则x+y-z的值为
若x:y:z=3:5:7,3x+2y-4z=9,则x+y+z的值为( )
已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值
若5分之x=4分之y=3分之z(z不等于0),则3x-2y分之x+y+z的值为
若z≠0,且4x=7y+5z,2x+y=z,求x,y,z的值
若x:y:z=3:4:6,则x-y+z分之x+y-z的值为?
若2x+5y+4z=0,3x+y-7z=0,则x+y-z的值等于( )
若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值
x*x+y*y+2z*z-2x+4y+4z+7=0,求xyz的值
若x/3=y/4=z/5,求x+y+z/3x-2y+z的值.
已知4X=7Y+5Z,2X+Y=Z,那么X:Y:Z的值是?