Astatement that can be expressed in if-then from is

Which fraction below is equivalent to 10/12?

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?

Using elimination, what is -4x+2y=-12 4x+8y=-24