Вопрос:

Ответ:

\[\sqrt{x^{2}} = \sqrt{2\sqrt{10} - 6} \cdot \sqrt{2\sqrt{10} + 6}\]

\[\sqrt{x^{2}} = \sqrt{40 - 36}\]

\[\sqrt{x^{2}} = \sqrt{4}\]

\[x^{2} = 4\]

\[x = \pm 2.\]