Cho \(\frac{{\log a}}{p} = \frac{{\log b}}{q} = \frac{{\log c}}{r} = \log x \ne 0;\;\frac{{{b^2}}}{{ac}} = {x^y}\).

* Hướng dẫn giải

\(\begin{array}{l}\frac{{{b^2}}}{{ac}} = {x^y} \Leftrightarrow \log \frac{{{b^2}}}{{ac}} = \log {x^y}\\ \Rightarrow y\log x = 2\log b - \log a - \log c = 2q\log x - p\log x - r\log x\\\quad \quad \quad \quad  = \log x\left( {2q - p - r} \right)\end{array}\)

\( \Rightarrow y = 2q - p - r\)(do \(\log x \ne 0\)).