Explanation:
x = temperature at midnight.
temperature at 5am = x - 16
temperature at 9am = 2×(temperature at 5am) =
= 2×(x - 16)
temperature at noon = temperature at 9am + 8 =
= 2×(x - 16) + 8 = 2x - 32 + 8 =
= 2x - 24
as you can see, something is missing. you left something out in the problem definition. like what was the final temperature at noon. then we would have an equation with one variable (x, the temperature at midnight) that we could solve.
without that we have now only an expression that describes the relation between the temperatures at midnight and at noon.
infinite many relation pairs (temperature at midnight, temperature at noon) can be created using 2x - 24 :
e.g.
(0, -24)
(24, 24)
(36, 48)
...
if we know e.g. the temperature at noon y, we would have then
y = 2x - 24
y + 24 = 2x
x = (y + 24)/2 = y/2 + 12
again, without that missing piece of information I can only give you the calculation rules of how to get the answer but not the specific answer.
that you have to do on your own based on the equation or expression above.