My teacher gave us the answers but we just need to show the work for solving the problems. Please help me

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?

Askate shop rents roller skates as shown on the table below. which graph and function models this situation?

Which best explains why this triangle is or is not a right triangle ?