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=_______
已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z
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x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=?
已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz
已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)
(x+y-z)(x-y+z)=
已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=?
已知2x+5y+4z=15.7x+y+3z=14 则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)
x/2=y/3=z/5 x+3y-z/x-3y+z
若{x+3y+10z=0 则 (x+y-z)/(x-y+z)