I assume that you want to know the temperature at a certain timing.
Well, you know that at 12:00 pm, the temperature was 12 F and that it decreases by a steady rate of 2 F each hour.
This means that at 1:00 pm, the temperature was 12-2 = 10 F
At 2:00 pm, the temperature was 10-2 = 8 F
At 3:00 pm, it was 8-2 = 6 F
.......and so on
You can follow this sequence to the timing you are looking for.
4/2 * 4/5 = (4*4) ^ (2*5) = 1 3/5 = 1.6
-9a + 11ad - 35a + ad = -44a + 12ad
hope this helps
