I am greater than 310. My number has 0 ones. The digits in my hundreds and tens places are the same

For how answer my question this will be the last question can you answer in math subject

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?

Graph the equationy= x+3[tex]y = x + 3[/tex]