Researchers in Antarctica discovered a warm sea current under a glacier that is causing the glacier to melt. The ice shelf of the glacier had a thickness of approximately 450 meters when it was first discovered. The thickness of the ice shelf is decreasing at an average rate of 0.06 meters per day. What is the function that can be used to find the thickness of the ice shelf in meters x days since the discovery? What are some key attributes and characteristics that are unique to this linear function?