Iam confused on what they are asking here? any ?

How is working backward similar to solving an equation?

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?

For what value of (y) is 3^3/3^y =1/9