Final answer:
The single equation representing X + 2y - 5 and the y-axis is X + 2y - 5 = 0 and x = 0.
Step-by-step explanation:
The equation that represents the line X + 2y - 5 = 0 and the y-axis is a system of equations where one equation represents the given line and the other equation represents the y-axis. The equation representing the y-axis is x = 0. So, the single equation that represents both X + 2y - 5 and the y-axis is:
X + 2y - 5 = 0 and x = 0
Learn more about Equations that represent a line and the y-axis