7th Class Mathematics Exponents and Power Question Bank Exponents and Power

  • question_answer
    Simplify\[\frac{{{\left( {{a}^{-n}} \right)}^{m}}\times {{a}^{-2m}}}{{{a}^{mn}}\times {{a}^{2m}}}\]

    A)  \[100\,{{a}^{\frac{25}{4}}}\]             

    B)  \[\frac{1}{100{{a}^{\frac{21}{4}}}}\]

    C) \[20{{a}^{\frac{-21}{4}}}\]     

    D)  \[20{{a}^{\frac{21}{4}}}\]

    Correct Answer: C

    Solution :

    (c) \[\frac{{{\left( {{a}^{-n}} \right)}^{m}}\times {{a}^{-2m}}}{{{a}^{mn}}\times {{a}^{2m}}}=\frac{{{a}^{-nm}}\times {{a}^{-2m}}}{_{a}\left( mn+2m \right)}=\frac{_{a}-\left( nm+2m \right)}{_{a}\left( mn+2m \right)}\] \[={{a}^{-(mn+2m)-(mn+2m)}}={{a}^{-2(mn+2m)}}={{a}^{-2m(n+2)}}\] 


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