SSC Sample Paper SSC CGL - Sample Paper-9

  • question_answer
    \[(\sqrt{2}+\sqrt{7-2\sqrt{10}})\] is equal to

    A)  \[\sqrt{2}\]                               

    B)  \[\sqrt{7}\]

    C)  \[\sqrt{5}\]                   

    D)  \[2\sqrt{5}\]

    Correct Answer: C

    Solution :

    Expression\[=\sqrt{2}+\sqrt{7-2\sqrt{10}}\] \[=\sqrt{2}+\sqrt{7-2\sqrt{5}\times \sqrt{2}}\] \[=\sqrt{2}+\sqrt{{{(\sqrt{5})}^{2}}+{{(\sqrt{2})}^{2}}-2\times \sqrt{5}\times \sqrt{2}}\] \[=\sqrt{2}+\sqrt{{{(\sqrt{5}-\sqrt{2})}^{2}}}\] \[=\sqrt{2}+\sqrt{5}-\sqrt{2}=\sqrt{5}\] 


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