若x/3=y/4=z/5≠0,求2x+y+3z/3x-2y-z的值.

若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 若x+2y-9z=0,x-2y+5z=0,(x.y.z≠=0)求2x平方+3y平方+7z平方/x平方-4y平方+4z平方 1.若3x-2y+z=2;3x+2y+5z=4,求x+22.若x-3y+z=0;3x-3y-4z=0,求x:y:z 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. 已知{x-5y+2z=0 3x-5y-4z=0,求x：y:z 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值 若xyz≠0且{4x-5y+2z=0 x+4y-3z=0 ,求x：y：z. 若x/3=y/4=z/5≠0,求2x+y+3z/3x-2y-z的值. 若xyz≠0且4x-5y=-2z,x+4y=3z,求x：y：z 设z≠0 x、y、z 满足4x-7y-5z=0 2x-y-z=0 求x：y 设z≠0,x、y、z满足4x-7y-5z=0、2x-y-z=0,求x:y 已知4x-3y-6z=0,x+2y-7z=0,且x,y,z≠0,求2x+3y+6z/x+5y+5z的值. 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知3x+4y+5z=0,2x+3y-4z=0,求(x+y+z)/(x-y+z) 已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值. 已知{3x+4y+5z=0,2x+3y-4z=0,求x+y+z/x-y+z的值. 2x+3y-4z=0,3x+4y+5z=0,求x+y-z/x-y+z的值