Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If \( {x }^{ 2} \) + x = 41

find \( {(x + 7) }^{ 2} \) + \(\frac{1}{(x+7)^2}\)

Options:

190

148

167

207

Correct Answer:

167

Explanation:

Let x + 7 = t

x = t - 7

Put in \( {x }^{ 2} \) + x = 41

⇒ (t - 7)2 + t - 7 = 23

⇒ t2 + 49 - 14t + t - 7 = 41

⇒ t2 - 13t + 1 = 0

⇒ t + \(\frac{1}{t}\) = 13

⇒ t2 +\(\frac{1}{ {t }^{2 }}\) = 132 - 2 = 167