\(A=\sqrt{6+\sqrt{6+\sqrt{6}}}+\sqrt{2+\sqrt{2+\sqrt{2}}}\)
\(A< \sqrt{6+\sqrt{6+\sqrt{9}}}+\sqrt{2+\sqrt{2+\sqrt{4}}}\)
\(=\sqrt{6+\sqrt{6+3}}+\sqrt{2+\sqrt{2+2}}\)
\(=\sqrt{6+\sqrt{9}}+\sqrt{2+\sqrt{4}}\)
\(=\sqrt{6+3}+\sqrt{2+2}\)
\(=\sqrt{9}+\sqrt{4}\)
\(=3+2=5=B\)
Vậy \(A< B\).