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SSC CGL 2022 PYQ — Question 67

SSC CGL - 03 Dec 2022 - Shift 1 • Quantitative Aptitude • Q67

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If X−1X=13X-{{1} \over X}=13,  what will be the value of X4+1X4=?X^4+{{1} \over X^4}=? 

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Correct answer: D

Explanation

The correct answer is Option 4 i.e. 29239.

Formula used:

(a - b)2 = a2 + b2 - 2ab           ---- (1)

Calculations:

Using equation (1), we get

⇒ (x - 1/x)2 = x2 + 1/x2 - 2

⇒ 132 = x2 + 1/x2 - 2

⇒ x2 + 1/x2 = 171

Again, (x2 + 1/x2)2 = x4 + 1/x4 + 2

⇒ 1712 = x4 + 1/x4 + 2

⇒ x4 + 1/x4 = 29241 - 2

⇒ x4 + 1/x4 = 29239