\[x^{2} + \frac{1}{x^{2}} = 14\]
\[x^{2} + 2 + \frac{1}{x^{2}} = 14 + 2\]
\[\left( x + \frac{1}{x} \right)^{2} = 16\]
\[x + \frac{1}{x} = \pm 4.\]