Ta có AD BĐT $\sqrt{ab}\leq \frac{a+b}{2}$+ $ \sqrt{x-17}\leq \frac{1+x-17}{2}$
+ $\sqrt{y-12} \leq \frac{1+y-12}{2}$
+$ \sqrt{z-2014} \leq \frac{1+z-2014}{2}$
Cộng từng vế:
$\Rightarrow \sqrt{x-17}+\sqrt{y-12}+\sqrt{z-2014}\leq \frac{x-16+y-11+z-2013}{2}$
$\Rightarrow VP \leq \frac{x-16+y-11+z-2013+2040}{2}=\frac{x+y+z}{2}$ (đpcm)
Đúng thì tích cho cái nhé :))