Is the mapping a function or not a function? explain. a. yes. because every x-value is assigned to only one y - value. b. yes, because every y- value is a sign to only one x- value. c. no, because the x -value to it’s a sign to y-value 7. d. no, because functions cannot have negative numbers. ? !

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?