ÁP dụng hđt (a+b+c)2 =a2 +b2 +c2 +2ab+2ac+2bc
\(\Rightarrow\) \(\sqrt{10+2\sqrt{6}+2\sqrt{10}+2\sqrt{15}}=\sqrt{2+3+5+2\sqrt{2}\times\sqrt{3}+2\sqrt{2}\times\sqrt{5}+2\sqrt{3}\times\sqrt{5}}=\sqrt{\left(\sqrt{2}+\sqrt{3}+\sqrt{5}\right)^2}=\left|\sqrt{2}+\sqrt{3}+\sqrt{5}\right|=\sqrt{2}+\sqrt{3}+\sqrt{5}\)