Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If a + \(\frac{1}{a + 3}\) = 3

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

Options:

198

178

216

242

Correct Answer:

198

Explanation:

Given = a + \(\frac{1}{a + 3}\) = 3

By adding 3 on both sides we get,

(a + 3) + \(\frac{1}{a + 3}\) = 3 + 3 = 6

(a + 3)3 + \(\frac{1}{(a + 3)^3}\) = 63 - 3 × 6 = 198

 

Note - if x +  \(\frac{1}{x}\) = a

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