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Basic Operations & Factorization
Linear Equations
Quadratic Equations

If (x + 1/x) = 4, then (x4 + 1/x4) is equal to :

Answer: B. 194

x + 1/x = 4 → ( x + 1/x)2 = 16 → x2 + 1/x2 + 2 = 16 → x2 +1/x2 = 14

Now,

x2 + 1/x2 = 14 → ( x2 + 1/x2)2 = 196 → x4 + 1/x4 + 2 = 196 → x4 +1/x4 = 194.

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