CLAT Sample Paper CLAT Sample Paper-11

  • question_answer
    If \[\left( x+\frac{1}{x} \right)=3,\] then the value of \[\left( {{x}^{6}}+\frac{1}{{{x}^{6}}} \right)\] is

    A)  927                 

    B)        414                 

    C)        364                             

    D)        322                 

    Correct Answer: D

    Solution :

    \[\therefore \]      \[x+\frac{1}{x}=3\,\,\,\Rightarrow \,\,{{\left( x+\frac{1}{x} \right)}^{3}}=27\] \[\Rightarrow \]   \[{{x}^{3}}+\frac{1}{{{x}^{3}}}+3\times x\times \frac{1}{x}\,\left( x+\frac{1}{x} \right)=27\] \[\Rightarrow \]   \[{{x}^{3}}+\frac{1}{{{x}^{3}}}=18\] \[\Rightarrow \]   \[{{\left( {{x}^{3}}+\frac{1}{{{x}^{3}}} \right)}^{2}}=324\] \[\Rightarrow \]   \[{{x}^{6}}+\frac{1}{{{x}^{6}}}+2=324\] \[\Rightarrow \]   \[{{x}^{6}}+\frac{1}{{{x}^{6}}}=322\]


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