Обчислити значення виразу log15 16*log16 17*log17 18*log18 225

\(=\frac{log_{16}{17}}{log_{16}{15}}*\frac{log_{18}{225}}{log_{18}{17}} = log_{15}{17}*log_{17}{225} = \frac{log_{17}{225}}{log_{17}{15}} =log_{15}{225} = 2 \)

\(\log_{a}{b} = \frac{1}{\log_{b}{a}}.\)

\( {\log_{a}{b} = \frac{\log_{c}{b}}{\log_{c}{a}}}.\)