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SSC CGL 2021 PYQ — Question 57

SSC CGL - 24 Aug 2021 - Shift 1 • Quantitative Aptitude • Q57

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If x+1x=7x+\dfrac{1}{x}=7, than x2+1x2x^2+\dfrac{1}{x^2} is equal to :

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 47

x + 1/x = 7 

On squaring both sides we get,

x2 + 1/x2 + 2 = 49

x2 + 1/x2 = 49 - 2 = 47.