[tex]\bf f(x)=y=ln(x)\qquad
\begin{cases}
x=1\\
y=ln(1)\to y=0
\end{cases}\\\\
-----------------------------\\\\
\left. \cfrac{dy}{dx}=\cfrac{1}{x} \right|_{x=1}\implies 1\impliedby m
\\\\\\
\textit{now, we know that }
\begin{cases}
x=1\\
y=0\\
m=1
\end{cases}\implies y-0=1(x-1)\implies y=x-1[/tex]
now, you're asked to use it when ln(1.38), which is just another way of saying x = 1.38
so set x = 1.38 and see what "y" is
