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SSC Selection Post 2020 PYQ — Question 61

SSC Selection Post - Graduation Level 2020 - 10 Nov 2020 - Shift 3 • Quantitative Aptitude • Q61

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If x2−32x+1=0x ^ 2 - 3\sqrt2 x + 1 = 0 , then the value of x3+1x3x ^ 3 + \frac{1}{x ^ 3} is:

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Correct answer: A

Explanation

The correct answer is Option 1 i.e. 45245\sqrt2.

x2 - 3√2x + 1 = 0

⇒ x + 1/x = 3√2

⇒ x3 + 1/x3 = (3√2)3 - 3(3√2) = 54√2 - 9√2 = 45√2