SSC Sample Paper SSC CGL - Sample Paper-3

  • question_answer
    \[2{{a}^{2}}+2{{b}^{2}}+2{{c}^{2}}-2ab-2bc-2ca=?\]

    A)  \[{{(a-b)}^{2}}-{{(b-c)}^{2}}+{{(c-a)}^{2}}\]

    B)  \[{{(a-b)}^{2}}+{{(b-c)}^{2}}-{{(c-a)}^{2}}\]

    C)  \[{{(a-b)}^{2}}-{{(b-c)}^{2}}-{{(c-a)}^{2}}\]

    D)  \[{{(a-b)}^{2}}+{{(b-c)}^{2}}+{{(c-a)}^{2}}\]

    Correct Answer: D

    Solution :

    \[2{{a}^{2}}+2{{b}^{2}}+2{{c}^{2}}-2ab-2bc-2ca\] \[=({{a}^{2}}-2ab+{{b}^{2}})+({{b}^{2}}-2bc+{{c}^{2}})+({{c}^{2}}-2ca+{{a}^{2}})\]\[={{(a-b)}^{2}}+{{(b-c)}^{2}}+{{(c-a)}^{2}}\]


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