#### Answer

$y=1$

#### Work Step by Step

RECALL:
The graph of $y=k$ where $k$ is any real number is a horizontal line whose y-intercept is $k$. All points on the line have a y-coordinate of $k$.
Thus, the graph of the given equation is a horizontal line .
The horizontal line passes through the point $(5, 1)$. This means that all points on the line have a y-coordinate of $1$.
Therefore, the equation of the horizontal line that passes through the point $(5, 1)$ is:
$y=1$