Boris rented a truck for one day. There was a base fee of $16.99, and there was an additional charge of 88 cents for each mile driven. Boris had to pay 138.43 when he returned the truck. For how many miles did he drive the truck?

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?