8th Class Mathematics Factorisation Question Bank Factorization

  • question_answer
    Factorize \[{{\mathbf{a}}^{\mathbf{3}}}-\mathbf{2}\sqrt{\mathbf{2}}{{\mathbf{b}}^{\mathbf{3}}}\]is

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

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

    C)  \[(a-\sqrt{2}b)({{a}^{2}}-\sqrt{2}ab+2{{b}^{2}})\]             

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

    Correct Answer: B

    Solution :

    (b): \[{{a}^{3}}-3\sqrt{2}{{b}^{3}}\] \[={{a}^{3}}-{{(\sqrt{2}b)}^{3}}\] Then use formula, \[{{a}^{3}}-{{b}^{3}}=\left( a-b \right)\left( {{a}^{2}}+ab+{{b}^{2}} \right).\]


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