Exams › SSC CGL (Prelims) › General

If x + 1/x = 3, find the value of (x^6 + 1/x^6) - 2(x^4 + 1/x^4) + 3(x^2 + 1/x^2).

1. 235
2. 249
3. 256
4. 261

Correct answer: 249

Solution

From x + 1/x = 3: x^2 + 1/x^2 = 7, x^4 + 1/x^4 = 47, and x^6 + 1/x^6 = 322. Substituting: 322 - 2(47) + 3(7) = 322 - 94 + 21 = 249.

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