Final answer:
The equation representing the cost c for d days at Healthy Gym, which has an initial fee of $5 and then $2 per day, is c = 5 + 2d.
Step-by-step explanation:
The cost c for d days at Healthy Gym, which includes an initial fee of $5 and then $2 per day, can be represented by the linear equation:
c = 5 + 2d
Where c is the total cost and d is the number of days.
This equation indicates that for each day spent at the gym, the cost increases by $2, starting with a one-time initial fee of $5.