Answer:
Cost with 45 songs: $46.75
Cost with s songs: $13 + (s * $0.75)
Step-by-step explanation:
First multiply the number of songs by the cost per song (45 * $0.75 = $33.75), then add the monthly service cost to that number ($13 + $33.75 = $46.75) to get the total monthly cost to Pedro.