A cab charges customers a one time fee plus a fee per mile driven. If the cab drove someone for 7 miles and charged them $42 and also drove someone else for 10 miles and charged them $57. What is the rate of change in this scenario?

Masons cell phone company charges $0.12 for every text message he sends plus $2.50 per month if mason sent 25 messages this month how much money does he owe the one with the correct answer and explanation gets 10 points and is marked as the brainliest answer