Answer:
-4°C
Explanation:
At the beginning of the chemistry experiment the temperature of the liquid was -5°C and it dropped 9°C so you do:
-5°C - 9°C = -14°C
The answer is -14°C for the first part of the question because when you are subtracting a positive number from a negative number you have to add the two numbers together but your answer will always be a negative number.
Then you add 25°C to -14°C:
-14°C + 25°C = 11
Because when adding a negative number to a positive number that is bigger than the negative number you have to subtract but your answer will always be a positive number, however if the positive number is smaller than the negative number your answer will be a negative number.
Then you subtract 11°C from 15°C:
11°C - 15°C = -4°C
Because when you subtract a number that is bigger than the first number you get a negative number.