Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If \(\sqrt {x}\) + \(\frac{1}{\sqrt {x}}\) = 3, then find the value of x2 (x2 - 47).

Options:

0

2

-1

-2

Correct Answer:

-1

Explanation:

Given, \(\sqrt {x}\) + \(\frac{1}{\sqrt {x}}\) = 3

After squaring ⇒

⇒ x + \(\frac{1}{x}\) = 32 - 2 = 7

⇒ x2 + \(\frac{1}{x^2}\) = 72 - 2 = 47

Put value of 47 in  ⇒ x2 (x2 - 47))

⇒  x2 (x2 - x2 - \(\frac{1}{x^2}\)) = x2 × (-) \(\frac{1}{x^2}\) = -1