\(P=\sqrt{\left(x+1995\right)^2}+\sqrt{\left(x+1996\right)^2}\)
\(P=\left|x+1995\right|+\left|x+1996\right|\)
\(P=\left|-x-1995\right|+\left|x+1996\right|\)
\(P\ge\left|-x-1995+x+1996\right|=1\)
\(\Rightarrow P_{min}=1\) khi \(\left\{{}\begin{matrix}x+1995\le0\\x+1996\ge0\end{matrix}\right.\) \(\Rightarrow-1996\le x\le-1995\)