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    If x=2−3x=2-\sqrt3x=2−3​​, then x−1xx - \frac{1}{x}x−x1​​ is:
    Question

    If x=23x=2-\sqrt3​, then x1xx - \frac{1}{x}​ is:

    A.

    1230312-30\sqrt3​​

    B.

    535\sqrt3​​

    C.

    23-2\sqrt3​​

    D.

    333\sqrt3​​

    Correct option is C

    Given:

    x=23x = 2 - \sqrt{3}​​​

    We need to find the value of x1x.x - \frac{1}{x}.​​

    Solution:

    1x=123×2+32+3=2+3(23)(2+3)\frac{1}{x} = \frac{1}{2 - \sqrt{3}} \times \frac{2 + \sqrt{3}}{2 + \sqrt{3}} = \frac{2 + \sqrt{3}}{(2 - \sqrt{3})(2 + \sqrt{3})}=2+343\frac{2+\sqrt3}{4- 3}​​

    Thus, we have:

    1x=2+3\frac{1}{x} = 2 + \sqrt{3}​​

    Now we can compute:

    x1x=(23)(2+3)x - \frac{1}{x} = (2 - \sqrt{3}) - (2 + \sqrt{3})​​

    x1x=2323=23x - \frac{1}{x} = 2 - \sqrt{3} - 2 - \sqrt{3} = -2\sqrt{3}

    Option (C) is right.

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