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    • Question

      If [x + (1/x)] = 7, find the value of [x⁴ +

      (1/x⁴)].
      A 1,201 Correct Answer Incorrect Answer
      B 6.520 Correct Answer Incorrect Answer
      C 2,207 Correct Answer Incorrect Answer
      D 5,450 Correct Answer Incorrect Answer

      Solution

      ATQ,

      x + (1/x) = 7

      Squaring both sides:

      [x + (1/x)]² = 7²

      Using identity: (a + b)² = a² + 2ab + b²

      x² + (1/x²) + 2 = 49

      So, x² + (1/x²) = 49 - 2 = 47

      Squaring again:

      [x² + (1/x²)]² = 47² = 2,209

      So, x⁴ + (1/x⁴) + 2 = 2,209

      Therefore, x⁴ + (1/x⁴) = 2,209 - 2 = 2,207

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