A newly appointed school district superintendent releases a plan for the next 20 years that affects the schools within the boundaries of the district. In this plan, there is new policy that states that if a high school has less than 100 students, then the school will be shut down. Calamanco High School has a population of 1,417 students, but it is losing students at an average rate of 109 students per year. This school used to house more than 5,000 students but the district has been struggling in recent years and losing people to more affluent nearby districts and cities. Some communities are concerned about this decreasing rate because there will be a time when the district may shut the school down. Let x represent the number of full years that the school is operational. Part A: If this trend continues, write a function that gives the student population at Calamanco High School after x years before the school is shut down by the district.

Part B: What constraints does this situation put on the domain and range of the function?