Final answer:
The polynomial for the difference in earnings is -c² + 15c + 100. The polynomial for the combined earnings is 3c² + c - 300.
Step-by-step explanation:
The polynomial for Darnell's profit is (c²) + 8c - 100, and the polynomial for Stephanie's profit is 2c² - 7c - 200.
To find the polynomial for the difference in their earnings, we subtract Stephanie's profit polynomial from Darnell's profit polynomial. So the polynomial for the difference is (c²) + 8c - 100 - (2c² - 7c - 200). Simplifying this expression, we get -c² + 15c + 100.
To find the polynomial for their combined earnings, we add Darnell's profit polynomial and Stephanie's profit polynomial. So the polynomial for the combined earnings is (c²) + 8c - 100 + (2c² - 7c - 200). Simplifying this expression, we get 3c² + c - 300.