Answer:
28°
Explanation:
Let's take 'x' as the number of how much degrees it dropped. So this is how the equation will look like:
-2 - x = -30
It is '-x' since the temperature 'decreased', so you must a subtract.
Take -30 to the other side and substitute it with '-x'. Since both the terms are shifted, -30 will be +30 and -x will be +x (which is equivalent to x).
x = -2 + 30
x = 28°
∴ There was a 28° drop.