Final answer:
The cost equation for Car A is Cost_A = 20000 + 1000y and for Car B is Cost_B = 500 + 22500y.
Step-by-step explanation:
For Car A, the correct cost equation is Cost_A = 20000 + 1000y.
For Car B, the correct cost equation is Cost_B = 500 + 22500y.
The cost equations represent the relationship between the cost of the car and the value of y, which could be the number of years or any other variable of interest. The equation helps determine the total cost based on the value of y by multiplying it with the corresponding coefficient and adding the constant term.