Question

$Log \frac{1}{5} 125$

Answer 1

$\log_{ \frac{1}{5} }125= \dfrac{\log_{ 5 }125}{\log_{5 }\dfrac{1}{5} } = \dfrac{\log_{ 5 } 5^{3} }{\log_{5 } 5^{-1} } = \dfrac{3.\log_{ 5 } 5 }{-1.\log_{5 } 5 } = \dfrac{3.1 }{-1.1 } =-3$