CAASPP Math Practice Exam - California Test Prep, Practice Test & Study Guide

The equation of a vertical line is defined by the x-coordinate of points that lie on the line, since a vertical line does not change in the x-direction—it remains constant. Given the point (2, 3), the x-coordinate is 2. Therefore, the line passing through this point will maintain the x-value of 2 for all y-values.

Thus, the correct equation to represent this vertical line is x = 2. This indicates that for any value of y, the x-coordinate will always be 2, defining a vertical line on the Cartesian plane.

The other options define either horizontal lines or do not represent a vertical line. For instance, y = 2 or y = 3 would indicate horizontal lines, reflecting constant y-values instead.