SSC Sample Paper Mock Test-4 SSC CGL Tear-II Paper-1

  • question_answer
    The expression \[{{\left( \frac{{{x}^{a}}}{{{x}^{b}}} \right)}^{{{a}^{2}}+\,\,ab\,\,+\,\,{{b}^{2}}}}\times {{\left( \frac{{{x}^{b}}}{{{x}^{c}}} \right)}^{{{b}^{2\,\,+\,\,bc\,\,+\,\,{{c}^{2}}}}}}\times {{\left( \frac{{{x}^{c}}}{{{x}^{a}}} \right)}^{{{c}^{2}}+\,\,ac\,\,+\,\,{{a}^{2}}}}\]is equal to

    A)  1        

    B)  \[-\,\,1\]

    C)  0                                

    D)  None of these

    Correct Answer: A

    Solution :

    As given,                 \[{{\left( \frac{{{x}^{a}}}{{{x}^{b}}} \right)}^{{{a}^{2}}+ab+{{b}^{2}}}}\times {{\left( \frac{{{x}^{b}}}{{{x}^{c}}} \right)}^{{{b}^{2}}+bc+{{c}^{2}}}}\times {{\left( \frac{{{x}^{c}}}{{{x}^{a}}} \right)}^{{{c}^{2}}+ac+{{a}^{2}}}}\] \[={{x}^{(a-b)({{a}^{2}}+ab+{{b}^{2}})}}\times {{x}^{(b-c)({{b}^{2}}+bc+{{c}^{2}})}}\times {{x}^{(c-a)({{c}^{2}}+ac+{{a}^{2}})}}\] \[={{x}^{{{a}^{3}}-{{b}^{3}}}}\cdot {{x}^{{{b}^{3}}-{{c}^{3}}}}\cdot {{x}^{{{c}^{3}}-{{a}^{3}}}}\] \[[\because ({{a}^{3}}-{{b}^{3}})=(a-b)({{a}^{2}}+ab+{{b}^{2}})]\] \[={{x}^{{{a}^{3}}-{{b}^{3}}+{{b}^{3}}-{{c}^{3}}+{{c}^{3}}-{{a}^{3}}}}={{x}^{0}}=1\]                     


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