Question

saaeassw

Answer 1

If you start with
\[ M = \log A - \log A_0 \]
\[ M= \log \frac{A}{A_0} \\
\]
what base is this log? We usually assume base 10 if not specified, and thus
\[ 10^M= \frac{A}{A_0} \\ A= A_0 \ 10^M
\]
that does not look like your expression posted up top.