\[5x^{2} - 10 = 0\]
\[5 \cdot \left( x^{2} - 2 \right) = 0\]
\[5 \cdot \left( x - \sqrt{2} \right)\left( x + \sqrt{2} \right) = 0\]
\[x = \pm \sqrt{2}.\]
\[Ответ:x = \pm \sqrt{2}.\]