What is the slope of this function?

Which system of linear inequalities is represented by the graph?

Divide: 1573 ÷ 7 = a) 222 r5 b) 223 r6 c) 224 r5 d) 224 r3

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?