3x=4y 2y=5z 试求x:y:z

已知3x=4y,2y=5z,试求x:y:z 3x=4y 2y=5z 试求x:y:z 已知x:y:z=3:4:5,3x+2y-4z=18.求：x+y+z. 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z x/3=y/4=z/5,求x+y+z/3x-2y+z的值, 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z 已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值 已知x/4=y/5=z/6,求x+y+z/3x-2y+z的值. 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z.