\[\left( 2\sqrt{7} - \sqrt{2} \right)\left( \sqrt{7} + 6\sqrt{2} \right) =\]
\[= 2 \cdot 7 + 12\sqrt{14} - \sqrt{14} - 6 \cdot 2 =\]
\[= 14 + 11\sqrt{14} - 12 =\]
\[= 2 + 11\sqrt{14}\]