SSC Sample Paper SSC CHSL (10+2) Sample Test Paper-23

  • question_answer
    If \[x=y=111\] and \[z=112,\]then the value of \[{{x}^{3}}+{{y}^{3}}+{{z}^{3}}-3xyz\] is-

    A)  330                             

    B)  332

    C)  333                             

    D)  334

    Correct Answer: D

    Solution :

     \[{{x}^{3}}+{{y}^{3}}+{{z}^{3}}-3xyz\] \[=\,\,\,\,\,\frac{1}{2}\,(x+y+z)\,\,[{{(x-y)}^{2}}+{{(y-z)}^{2}}+{{(z-x)}^{2}}]\] \[=\,\,\,\,\,\frac{1}{2}\,(111+111+112)\,[{{(111-111)}^{2}}+\] \[{{(111-112)}^{2}}+{{(112-111)}^{2}}]\] \[=\,\,\,\,\,\frac{1}{2}\times 334\,\,[0+1+1]\] \[=\,\,\,\,\,\frac{1}{2}\times 334\,\times 2=\underline{\mathbf{334}}\]


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