A landscaper is working on a plot of land that is 409 feet above sea level on its western border. The land slopes upward from west to east on both sides of the border with a vertical change horizontal change ratio of 18 13. The expression 18 13x+992 models the elevation of the land on both sides of the​ border, with x representing distance east from the border. A neighbor directly to the west asks the landscaper to calculate the elevation of a point exactly 247 feet west of the​ border, at x=−247. Find the elevation of that point.