If x^4 + 16/(x^4)= 27217, x > 0, then the value of x + 2/x is :

If x⁴ + \(\frac{1}{x^4}\) = a

then x² + \(\frac{1}{x^2}\) = \(\sqrt {a + 2}\) = b

and x + \(\frac{1}{x}\) = \(\sqrt {b + 2}\)

If $x^4 + \frac{16}{x^4}$ = 27217, x > 0,

= x² + \(\frac{4}{x^2}\) = \(\sqrt {27217 + 2 \times 4}\) = 165

then the value of $x + \frac{2}{x}$ = \(\sqrt {165 + 2 × 2 }\) = 13