Question 5.

For some positive real number x , if log3(x)+logx(25)logx(0.008)=163\log _{\sqrt{3}}(x)+\frac{\log _x(25)}{\log _x(0.008)}=\frac{16}{3}, then the value of log3(3x2)\log _3\left(3 x^2\right) is

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Question Explanation

Text Explanation

It is given that log3(x)+log3(25)log3(0.008)=163 \log_{\sqrt{3}}(x) + \frac{\log_3(25)}{\log_3(0.008)} = \frac{16}{3} , which can be written as:

=> 2log3x+log0.00825=163 2 \log_3 x + \log_{0.008} 25 = \frac{16}{3}

=> 2log3x+log8100025=163 2 \log_3 x + \log_{\frac{8}{1000}} 25 = \frac{16}{3}

=> 2log3x+log112525=163 2 \log_3 x + \log_{\frac{1}{125}} 25 = \frac{16}{3}

=> 2log3x+log53(5)2=163 2 \log_3 x + \log_{5^{-3}} (5)^2 = \frac{16}{3}

=> 2log3x23=163 2 \log_3 x - \frac{2}{3} = \frac{16}{3}

=> 2log3x=163+23 2 \log_3 x = \frac{16}{3} + \frac{2}{3}

=> 2log3x=6 2 \log_3 x = 6

=> log3x2=6x2=36 \log_3 x^2 = 6 \Rightarrow x^2 = 3^6

Hence, log3(3x2)=log3(336)=log337=7 \log_3 \left(3 \cdot x^2\right) = \log_3 \left(3 \cdot 3^6\right) = \log_3 3^7 = 7

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