Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If (a2 - 16) = \(\frac{-2}{a^2}\), then find \(\sqrt { \frac{156\;a^2\;×\;250}{13\;a^4\;+\;104\;a^2\;+\;26} }\)

Options:

5\(\sqrt {7}\)

5\(\sqrt {5}\)

7\(\sqrt {5}\)

10\(\sqrt {5}\)

Correct Answer:

5\(\sqrt {5}\)

Explanation:

⇒ a2 - 16 = \(\frac{-2}{a^2}\)

⇒ a2 + \(\frac{2}{a^2}\) = 16

Now,

⇒ \(\sqrt { \frac{156\;a^2\;×\;250}{13\;a^4\;+\;104a^2\;+\;26}}\)

⇒ \(\sqrt { \frac{156\;a^2\;×\;250}{a^2\;(13\;a^2\;+\;104\;+\;\frac{26}{a^2})}}\)

⇒ \(\sqrt { \frac{156\;×\;250}{13\left(a^2\;+\;\frac{2}{a^2}\right)\;+\;104} }\)

⇒\(\sqrt { \frac{156\;×\;250}{13\;×\;16\;+\;104} }\) = \(\sqrt { \frac{39000}{312} }\) = \(\sqrt {125}\) = 5\(\sqrt {5}\)