13.56x+10.16y+6.82z=1o.7 8.7x+43y+15.7z=11.1 x+y+z=87.25
(x+y-z)(x-y+z)=
X+Y+Z=?
已知x,y,z满足x/(y+z)+y/(z+x)+z/(x+y)=1,求代数式x2/(y+z)+y2/(x+z)+z2/
已知实数x,y,z满足x/(y+z)+y/(z+x)+z/(x+y)=1,求x2/(y+z)+y2/(z+x)+z2/(
f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)
已知 x/(y+z)+y/(z+x)+z/(x+y)=1
x+y+z=1 求xyz/(x+y)(y+z)(z+x)的最大值
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1
x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y----
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
若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x)