Answer:
3 (x + 5.50) = 111.75; the monthly Internet service is $31.75
Explanation:
Let
x = monthly cost of internet service
Each month they received $5.50 as a credit on the bill.
The Schwartz family spent a total of $111.75 for Internet service for 3 months.
Total cost of internet service for three months = 3(x + 5.550)
111.75 = 3(x + 5.50)
111.75 = 3x + 16.50
111.75 - 16.50 = 3x
95.25 = 3x
x = 95.25 / 3
= 31.75
x = $31.75