Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If a - \(\frac{1}{a - 5}\) = 11

Then find , (a - 5)3 - \(\frac{1}{(a - 5)^3}\)

Options:

222

243

234

300

Correct Answer:

234

Explanation:

Given = a - \(\frac{1}{a - 5}\) = 11

By subtracting 5 on both sides we get,

(a - 5) - \(\frac{1}{a - 5}\) = 11 - 5 = 6

(a - 5)3 - \(\frac{1}{(a - 5)^3}\) = 63 + 3 × 6 = 234

 

Note - if x -  \(\frac{1}{x}\) = a

then x3 - \(\frac{1}{x^3}\) =  a3 + 3a