Multiple Choice Question (MCQ)

If a^2-3a + 1 = 0, (a\ne 0 ), then the value of a^2 + \dfrac{1}{a^2} is

  1. ×

    4

  2. 7

  3. ×

    8

  4. ×

    13

Collected in the board: Nike function

Steven Zheng posted 4 hours ago

Answer

  1. a^2-3a + 1 = 0

    Divide both sides by a, then

    a + \dfrac{1}{a} =3

    Square both sides

    a^2 + \dfrac{1}{a^2} +2 = 9

    Then

    a^2 + \dfrac{1}{a^2} = 7

    Therefore

    B is the right choice

Steven Zheng posted 4 hours ago

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