Finite Mathematics, Chapter 1, Review Exercises, Section Review Exercises, Problem 12

Determine the slope of the line $x = 5y$
If we transform the given line into point slope form, we have

$
\begin{equation}
\begin{aligned}
x &= 5y \\
\\
5y &= x \\
\\
y &= \frac{1}{5}x
\end{aligned}
\end{equation}
$

Now that the line is in the slope intercept form $y = mx + b$. By observation, the slope is equal to $\displaystyle \frac{1}{5}$