Answer
\begin{align*}
(a)& \ m_s= \ln t+3.75 \\
(b)&\ m_t= \frac{s}{t}\\
(c) &\ m_s\bigg|_{t=3}= \ln (3)+3.75
\end{align*}
Work Step by Step
Given $$m(t, s)=s \ln t+3.75 s+14.96 $$
Since
\begin{align*}
(a)& \ m_s= \ln t+3.75 \\
(b)&\ m_t= \frac{s}{t}\\
(c) &\ m_s\bigg|_{t=3}= \ln (3)+3.75
\end{align*}
