A man shines a laser beam from a third-story window of a building onto the pavement below. The path of the laser beam is represented by the equation y = –(2/3)x + 30. In this problem, y represents the height above the ground, and x represents the distance from the face of the building. All height and distance measurements are in feet.
I know that the building if 30 feet high and the laser beam reaches out 45 feet from the face of the building.
The next question they ask is how to show your work for finding the height of the laser beam 30 feet out from the face of the building. I know it is 1

Question

A man shines a laser beam from a third-story window of a building onto the pavement below. The path of the laser beam is represented by the equation y = –(2/3)x + 30. In this problem, y represents the height above the ground, and x represents the distance from the face of the building. All height and distance measurements are in feet.
I know that the building if 30 feet high and the laser beam reaches out 45 feet from the face of the building.
The next question they ask is how to show your work for finding the height of the laser beam 30 feet out from the face of the building. I know it is 1