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    Question

    If x6 + 1 – √3x3 = 0 then x108 + x90 + 15?

    A 14 Correct Answer Incorrect Answer
    B 17 Correct Answer Incorrect Answer
    C 15 Correct Answer Incorrect Answer
    D 20 Correct Answer Incorrect Answer

    Solution

    x6 + 1 – √3x3 = 0 x6 + 1 = √3x3, divided this x3 x3 + 1/x3 = √3 And we know that if x + 1/x = √3 then x6 = -1 Here we have (x3)6 = - 1 that means x18 = -1 = (-1)6 + (-1)5 + 15 = 1 – 1 + 15 = 15

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