Câu hỏi 84
Cho $a,b,c\in(0,\infty)$. Chứng minh bất đẳng thức
$$\frac{a-\sqrt{bc}}{a+2(b+c)}+\frac{b-\sqrt{ca}}{b+2(c+a)}+\frac{c-\sqrt{ab}}{c+2(a+b)}\ge0.$$
$$\frac{a-\sqrt{bc}}{a+2(b+c)}+\frac{b-\sqrt{ca}}{b+2(c+a)}+\frac{c-\sqrt{ab}}{c+2(a+b)}\ge0.$$