Resolute academy algebra 1

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?

Write the expression 7x^3-28xy^2 as the product of 3 factors

Write as a product: ac^2–ad+c^3–cd–bc^2+bd