9th Class Mathematics Number System and its Operations Question Bank Number Systems

  • question_answer
    If \[{{2}^{x-3}}{{.3}^{2x-8}}=36,\] then the value of \[x\]is______.

    A)  2                                

    B)  5        

    C)  3                    

    D)         1        

    Correct Answer: B

    Solution :

    We have \[{{2}^{x-3}}{{.3}^{2x-8}}=36\] \[\Rightarrow \]\[{{2}^{x}}{{2}^{-3}}{{.3}^{2x}}{{3}^{-8}}=36\] \[\Rightarrow \]\[{{2}^{x}}.\frac{1}{{{2}^{3}}}{{.3}^{x}}{{.3}^{x}}.\frac{1}{{{3}^{8}}}=36\] \[\Rightarrow \]\[{{(2\times 3\times 3)}^{x}}=36\times 8\times 6561\] \[\Rightarrow \]\[{{(18)}^{x}}={{(18)}^{5}}\] On comparing. We get \[\,x=5\]


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