\(=\frac{\left(2-\sqrt{3}\right)\cdot\sqrt{2}\cdot\sqrt{26+15\sqrt{3}}-\left(2+\sqrt{3}\right)\cdot\sqrt{2}\cdot\sqrt{26-15\sqrt{3}}}{\sqrt{2}}\)
\(=\frac{\left(2-\sqrt{3}\right)\cdot\sqrt{52+2\sqrt{675}}-\left(2+\sqrt{3}\right)\cdot\sqrt{52-2\sqrt{675}}}{\sqrt{2}}\)
\(=\frac{\left(2-\sqrt{3}\right)\cdot\sqrt{27+2\cdot\sqrt{27\cdot25}+25}-\left(2+\sqrt{3}\right)\cdot\sqrt{27-2\sqrt{27\cdot25}+25}}{\sqrt{2}}\)
\(=\frac{\left(2-\sqrt{3}\right)\left(3\sqrt{3}+5\right)-\left(2+\sqrt{3}\right)\left(3\sqrt{3}-5\right)}{\sqrt{2}}\)
\(=\frac{\left(\sqrt{3}+1\right)\left(\sqrt{3}-1\right)}{\sqrt{2}}=\frac{2}{\sqrt{2}}=\sqrt{2}\)