If (x + 1/x) = 3, then (x² + 1/x²) is equal to-

(a) 10/3
(b) 82/9
(c) 7
(d) 11

Anurag Mishra Professor Asked on 30th June 2016 in Maths.
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  • 1 Answer(s)

    Answer: (c) 7 

    Solution:-
    x + 1/x = 3 ………………… (1)

    Square on both side,
    (x + 1/x)^2 = 3^2
    x^2 + (1/x)^2 + 2 *x*1/x = 9
    x^2 + 1/x^2 + 2 = 9
    x^2 + 1/x^2 = 9 – 2
    x^2 + 1/x^2 = 7

    Hence, the correct answer is option is (c) 7.

    Anurag Mishra Professor Answered on 2nd July 2016.
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