The line x = -1 is a perfectly vertical line through x = -1. That means that any line that is perpendicular to it has to be a perfectly horizontal line, or a "y = " line. If a line goes through the point (2, 3) and is perpendicular to x = -1, it has to go through the y value of the point which is 3. Therefore, the line perpendicular to x = - 1 through the point (2, 3) is y = 3.