8th Class Mathematics Factorisation Question Bank Factorisation

  • question_answer
    Factors of \[{{x}^{4}}-{{(x-z)}^{4}}\] are __.

    A)  \[(2x+z)(2{{x}^{3}}+{{z}^{3}}-2{{x}^{2}})\]

    B)  \[z(x+2z)({{x}^{2}}+{{z}^{2}}-{{x}^{2}})\]

    C)  \[z(2x-z)(2{{x}^{2}}-2xz+{{z}^{2}})\]

    D)  \[z(x-2z)(2{{z}^{2}}-2xz+{{x}^{2}})\]

    Correct Answer: C

    Solution :

    \[{{x}^{4}}-{{(x-z)}^{4}}={{({{x}^{2}})}^{2}}-{{[{{(x-z)}^{2}}]}^{2}}\] \[=[{{x}^{2}}+{{(x-z)}^{2}}][{{x}^{2}}-{{(x-z)}^{2}}]\] \[=[{{x}^{2}}+{{(x-z)}^{2}}][\{x+(x-z)\}\{x-(x-z)\}]\] \[=[{{x}^{2}}+{{(x-z)}^{2}}][(2x-z)(z)]\] \[=(2x-z)z(2{{x}^{2}}+{{z}^{2}}-2xz)\]


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