Short Answer 
The function c(n) = 50 + 4n represents the gym’s monthly cost, where n is the number of visits. By substituting n with 7, the cost is calculated as c(7) = 50 + 4(7) = 78, meaning the monthly cost for 7 visits is $78.
Step 1: Understand the Function
The function given is c(n) = 50 + 4n, where c represents the monthly cost of the gym and n represents the number of visits to the gym. This means that the total cost increases by 4 for each additional visit beyond the base cost of 50.
Step 2: Substitute the Value
To find the cost when the number of visits is 7, substitute n with 7 in the function. This gives us:
- c(7) = 50 + 4(7)
Step 3: Calculate the Result
Now, perform the calculations step by step:
- First, calculate 4 times 7, which equals 28.
- Next, add this value to 50: 50 + 28.
- This results in 78, which is the monthly cost at n = 7 visits.