Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x4 + \(\frac{1}{x^4}\) = 15127, the positive value of x - \(\frac{1}{x}\) is?

Options:

9

11

13

18

Correct Answer:

11

Explanation:

x4 + \(\frac{1}{x^4}\) = 15127

x2 + \(\frac{1}{x^2}\) = \(\sqrt {15127 + 2}\) = 123

So, x - \(\frac{1}{x}\) = \(\sqrt {123 - 2}\) = 11