Chapter 4 - Exponential and Logarithmic Functions - Section 4.5 Properties of Logarithms - 4.5 Assess Your Understanding - Page 332: 73

$-3.880$

Change of Base Formula: $\hspace{20pt} \log_ a M = \dfrac{\log_b M}{\log_b a}$ $\log_{1/3} 71 = \dfrac{\log_{10} 71}{\log_{10} \dfrac{1}{3}}$ Where: $a=\dfrac{1}{3} \hspace{10pt} M = 71 \hspace{10pt} b = 10$ $ \dfrac{\log_{10} 71}{\log_{10} \dfrac{1}{3}} \approx \boxed{-3.880}$