All Exams Test series for 1 year @ ₹349 only
Question

If \(x + \dfrac{1}{x} = 17\), then the value of \(x^2 + \dfrac{1}{x^2}\) is:

This question was previously asked in
RRB Group D 2024 Question Paper PDF (27-Dec-2025) (Shift 2)
The correct answer is

287

Use the identity \(\left(x + \dfrac{1}{x}\right)^2 = x^2 + \dfrac{1}{x^2} + 2\).

Rearranging gives \(x^2 + \dfrac{1}{x^2} = \left(x + \dfrac{1}{x}\right)^2 - 2\).

Substitute \(x + \dfrac{1}{x} = 17\): \(x^2 + \dfrac{1}{x^2} = 17^2 - 2\).

So \(x^2 + \dfrac{1}{x^2} = 289 - 2 = 287\).

Hence, the value of \(x^2 + \dfrac{1}{x^2}\) is 287.

Was this answer helpful?

Similar Questions

  1. What is the value of (x + 2)2 − (x − 2)2 when x = 1?

  2. Simplify the following expression:

    (2a + 3b + 4c)2 + (2a − 3b − 4c)2 − 8a2 − 18b2 −32c2

  3. If a + b = 9 and ab = 13, then the value of a³ + b³ is:

  4. If a + b = 9 and ab = 13, then the value of \((a^2 + b^2)(a^3 + b^3)\) is:

  5. Expand \((a - p + m)^{2}\).

  6. If \(49a^{2} - b = \left(7a + \dfrac{1}{2}\right)\left(7a - \dfrac{1}{2}\right)\), then the value of b is:

  7. Simplify: \((2a + 3b)^2 - (2a - 3b)^2\)

  8. Simplify: (2x + 3y)(2x − 3y)

  9. Simplify: \((3\sqrt{5} + 2\sqrt{3})^{2} - (3\sqrt{5} - 2\sqrt{3})^{2}\).

  10. If \(x + \dfrac{1}{x} = \sqrt{20}\), find the value of \(x^{3} - \dfrac{1}{x^{3}}\), where \(x > 1\).


Important Questions from Identities

  1. If \(2x + { {1} \over 3x}= 5, x ≠ 0\) , then what is the value of  \(27x^3+{{1} \over 8x^3}\) ?

  2. If x 2 + 4y 2 = 40, xy = 6 and x > 2y then the value of x - 2y is:

  3. \(\dfrac{(5.17-2.19)^2-(5.17+2.19)^2}{11.3223}\)
  4. If a(a + b + c) 2= 1792; b(a + b + c) 2= 1536; c(a + b + c) 2= 768 then what will be the value of a?

  5. If a + b + c = 5, a 2+ b 2+ c 2= 27, a 3 + b 3 + c 3 = 125, then the value of  \(\frac{abc}{5}\)  is: 

Need Expert Advice?
Upcoming Exams
RRB JE
October 27, 2026
RRB ALP
November 03, 2026
Test Series
RRB Group D img
Railways
RRB Group D Mock Test Series 2026 (Latest Pattern)
1198 Tests 1 Tests Free
1854 Attempts
4.1(107)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App