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

  • question_answer
    If\[\sqrt{{{3}^{x}}}=243,\] then\[x=\]?

    A)  2                                

    B)  4            

    C)  6                                

    D)  10

    Correct Answer: D

    Solution :

    (d) \[\sqrt{3x}={{({{3}^{x}})}^{1/2}}\Rightarrow {{3}^{\frac{x}{2}}}=243\] (but \[243={{3}^{5}}\]) \[\therefore \]\[{{3}^{x/2}}={{3}^{5}}\Rightarrow \frac{x}{2}=5\Rightarrow x=10\]


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