Question

mn giúp e vs ạ 

C/m

a, \(\sqrt{21-6\sqrt{6}}+\sqrt{9+2\sqrt{18}}-2\sqrt{6+3\sqrt{3}}=0\)

b, \(\left(4+\sqrt{15}\right).\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}=2\)

Answer 1

a: \(=3\sqrt{2}-\sqrt{3}+\sqrt{6}+\sqrt{3}-\sqrt{2}\sqrt{12+6\sqrt{3}}\)

\(=3\sqrt{2}+\sqrt{6}-\sqrt{2}\left(3+\sqrt{3}\right)=0\)

b: \(=\left(4+\sqrt{15}\right)\left(\sqrt{5}-\sqrt{3}\right)\cdot\sqrt{8-2\sqrt{15}}\)

\(=\left(4+\sqrt{15}\right)\left(8-2\sqrt{15}\right)\)

\(=32-8\sqrt{15}+8\sqrt{15}-30=2\)