Lời giải:
\(H=\sqrt{x+2\sqrt{2x-4}}+\sqrt{x-2\sqrt{2x-4}}=\sqrt{(x-2)+2+2\sqrt{2(x-2)}}+\sqrt{(x-2)+2-2\sqrt{2(x-2)}}\)
\(=\sqrt{(\sqrt{x-2}+\sqrt{2})^2}+\sqrt{(\sqrt{x-2}-\sqrt{2})^2}\)
\(=|\sqrt{x-2}+\sqrt{2}|+|\sqrt{x-2}-\sqrt{2}|\)
Nếu $x\geq 4$ thì $H=\sqrt{x-2}+\sqrt{2}+\sqrt{x-2}-\sqrt{2}=2\sqrt{x-2}$
Nếu $2\leq x< 4$ thì $H=\sqrt{x-2}+\sqrt{2}+\sqrt{2}-\sqrt{x-2}=2\sqrt{2}$