If x + 1/x = 5, what will be the value of x² + 1/x²?

(a) 20
(b) 25
(c) 23
(d) 27

Anurag Mishra Professor Asked on 8th March 2016 in Maths.
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  • 1 Answer(s)

    Answer: (c) 23

    Solution:-
    x + 1/x = 5 
    Square on both side, 
    (x + 1/x)^2 = 5^2
    x^2 + 1/x^2 + 2 * x *1/x = 25
    x^2 + 1/x^2 + 2 = 25
    x^2 + 1/x^2 = 25 – 2
    x^2 + 1/x^2 = 23

    Then, the value of (x^2 + 1/x^2) is 23. 

    Hence, the correct answer is option (c) 23. 

    Anurag Mishra Professor Answered on 8th March 2016.
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