which integer represents the total change in altitude of an airplane descending 5 feet every second for 15 seconds
The integer that represents the total change in altitude of an airplane descending 5 feet every second for 15 seconds is -75 feet.
Explanation:
Each second the airplane descends 5 feet. So after 1 second, it will have descended 5 feet. After 2 seconds, it will have descended 10 feet (5 feet + 5 feet). After 3 seconds, it will have descended 15 feet (5 feet + 5 feet + 5 feet), and so on.
After 15 seconds, the airplane will have descended a total of 75 feet (5 feet + 5 feet + ... 15 times). However, we use a negative sign to indicate that this is a descent, so the final answer is -75 feet.