Final answer:
The expression representing the change in temperature in city B is -5° - 4°, which simplifies to -9°. The integer representing the change in temperature for city B is -9°.
Step-by-step explanation:
In city B, the temperature drops 5° from 8 am to 9 am and then it drops another 4° from 9 am to 10 am.
A. Expression Representing the Change in City B
To express the change in temperature as an algebraic expression, you sum up the individual temperature changes. Since the temperature is dropping, these will be negative numbers:
-5° + (-4°)
You can also simplify this expression by combining the temperature drops:
-5° - 4°
B. Integer Representing the Change in Temperature for City B
To find the overall change in temperature, you simply add the two changes together, keeping in mind that these are drops in temperature (negative changes):
-5 - 4 = -9°
So, the integer that represents the change in temperature for city B is -9°.