If x4 + \(\frac{1}{x^4}\) = 27887, the positive value of x + \(\frac{1}{x}\) is?

11 12 13 14

13

x4 + \(\frac{1}{x^4}\) = 27887 x2 + \(\frac{1}{x^2}\) = \(\sqrt {27887 + 2}\) = 167 So, x + \(\frac{1}{x}\) = \(\sqrt {167 + 2}\) = 13