Answer:
y = -3
Step-by-step explanation:
2y + 6 = 0
2y = -6
y = -3
Since it's just y = -3, there is NO SLOPE and it's just one straight line going horizontally.
So just pick the graph where it's a horizontal line that only goes through the y-axises of -3 (i.e (0, -3), (1, -3), and etc)