7th Class Mathematics Sample Paper Mathematics Sample Paper - 2

  • question_answer
    Simplify and express each of the following as exponential form:
    (a) \[\left( \frac{{{a}^{5}}}{{{a}^{3}}} \right)\times {{a}^{8}}\]                                
    (b) \[\frac{{{4}^{5}}\times {{a}^{8}}{{b}^{3}}}{{{4}^{5}}\times {{a}^{5}}{{b}^{2}}}\]
    (c) \[{{\left( {{2}^{3}}\times 2 \right)}^{2}}\]

    Answer:

    (a)        \[\left( \frac{{{a}^{5}}}{{{a}^{3}}} \right)\times {{a}^{8}}=({{a}^{5-3}})\times {{a}^{8}}\]
     = \[{{a}^{2}}\times {{a}^{8}}={{a}^{2+8}}={{a}^{10}}\]                                                                                            
    (b) \[\frac{{{4}^{5}}\times {{a}^{8}}{{b}^{3}}}{{{4}^{5}}\times {{a}^{5}}{{b}^{2}}}={{4}^{5-5}}\times {{a}^{8-5}}\times {{b}^{3-2}}\]                                                                                                     
    \[={{4}^{0}}\times {{a}^{3}}\times {{b}^{1}}\]
    \[=\text{ }1\times {{a}^{3}}\times b={{a}^{3}}b\]                                                                                         
    (c) \[{{\left( {{2}^{3}}\times 2 \right)}^{2}}={{\left( {{2}^{3}}+1 \right)}^{2}}={{\left( 24 \right)}^{2}}=28\]


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