## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$y=0$
RECALL: A horizontal line's equation is of the form $y=k$. Its y-intercept is $(0, 0)$, and each point on the line has a y-coordinate of $k$. The given graph is horizontal, and every point on the line has a y-coordinate of $0$. This means the equation of the line is $y=0$.