9．已知函数$f(x)$是定义在$R$上的偶函数，若对任意的$x_{1}$，$x_{2}\in [0$，$+\infty )$，且$x_{1}\ne x_{2}$，都有$(x_{1}-x_{2})(x_{1}f(x_{1})-x_{2}f(x_{2}))<0$成立，则不等式$\lambda f(\lambda )+(1-2\lambda )f(1-2\lambda )>0$的解集为$($　　$)$