已知x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=?
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
已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z
已知x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=?
已知x-y+z=0.3x+y-5z=0,则x+y+z/x+2y-3z=_______
若{x+3y+10z=0 则 (x+y-z)/(x-y+z)
已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=?
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+2y-4z=0,3x-y-z=0,则3x+2y+z/x+2y+z=
已知x+y-z=0,2x-y+2z=0 求(3x-2y+5z)/(5x-3y+2z)的值
已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少
已知x+2y-3z=0,2x+3y+5z=0,求(x+y+z)除以(x-y+z)
已知x,y,z,同时满足方程x+3y-5z=0,2x-y-3z=0求x:y:z的值