## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$y=2$
If the slope equals to $0$, we can surely state that the line is horizontal. The equation of a horizontal line is always in the form of: $y=a$, where $a$ is constant. Here, the point given is $(-3,2)$, which is on the line. For this point, $y=2$ and this should be true for the other points on the line. The equation is, therefore: $y=2$