Which second degree polynomial function has a leading coefficient of –1 and root 4 with multiplicity 2
f(x) = x3 – x2 – 4x + 4
f(x) = x4 – 3x2 – 4
f(x) = x4 + 3x2 – 4
f(x) = x3 + x2 – 4x – 4

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?