Multiple Choice Question (MCQ)

If x = \dfrac{2+\sqrt{3} }{2-\sqrt{3} } , then the value of (x-7)^2

  1. ×

    8

  2. ×

    4\sqrt{3}

  3. ×

    24\sqrt{3}

  4. 48

Collected in the board: Square Root

Steven Zheng posted 4 months ago

Answer

  1. x = \dfrac{2+\sqrt{3} }{2-\sqrt{3} }

    =\dfrac{2+\sqrt{3} }{2-\sqrt{3} } \cdot \dfrac{2+\sqrt{3}}{2+\sqrt{3}}

    =(2+\sqrt{3})^2

    =7+4\sqrt{3}

    (x-7)^2

    =(4\sqrt{3} )^2=48

Steven Zheng posted 4 months ago

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