SSC Quantitative Aptitude Algebra Question Bank Elementary Algebra (II)

  • question_answer
    If \[x=\sqrt{3}+\sqrt{2},\]then the value of\[\left( x+\frac{1}{x} \right)\]is

    A) \[2\]

    B) \[3\]

    C) \[2\sqrt{2}\]

    D) \[2\sqrt{3}\]

    Correct Answer: D

    Solution :

    [d] Given,\[x=\sqrt{3}+\sqrt{2}\] \[\therefore \]      \[\frac{1}{x}=\frac{1}{\sqrt{3}+\sqrt{2}}\] \[\frac{1}{x}=\frac{1}{\sqrt{3}+\sqrt{2}}\times \frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}-\sqrt{2}}\] (on rationalizing) \[=\frac{\sqrt{3}-\sqrt{2}}{3-2}=\sqrt{3}-\sqrt{2}\] \[\therefore \]      \[x+\frac{1}{x}=\sqrt{3}+\sqrt{2}+\sqrt{3}-\sqrt{2}=2\sqrt{3}\]


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