若2x+5y+4z=0 ,3x+y=0；则x+y-z=?

若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 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/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z= 若2x+5y+4z=0 ,3x+y=0；则x+y-z=? 已知{x-5y+2z=0 3x-5y-4z=0,求x：y:z 已知x+4y-3z=0,4x-5y+2z=0,则x：y：z 5x+4y+z=0 3x+y-4z=13 x+y+z=—2 若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值 X-Y-Z=0 X+Y-3Z=4 2X-5Y+7Z=21 2x+3y-z=9,x+y+z=15,5x-4y-z=0 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 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 若4x-3y-6z=0,x+2y-7z=0,则x+y+z/3x-y+z=? 若(4x-3y-3z)^2+|x-3y-z|=0 且xyz不等于0 则4x+y-z/x+y+z 的值 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z