Express one logarithmic quantity in terms of another
Let \(z=\log_{4}\left(s\right)\). The variable \(s\) is positive. The base \(4\) and every displayed logarithm base are positive and are not 1
\[4\log_{\left(4\right)^{2}}\left(\left(4\right)^{2}\,s^{-1}\right) - 3\log_{\left(4\right)^{3}}\left(\left(4\right)^{-2}\,s^{-1}\right)\]
Use exact logarithm laws and change of base