Answer: (b) 7.8 degrees
Step-by-step explanation: You need to pay attention to the number -8.4. It says the temperature changed by +2.7 degrees an hour for 6 HOURS. Therefore, your equation would be -8.4 + (2.7 * 6).
You have to solve whats in the parenthesis first, so your equation would end up being -8.4 + 16.2 making your answer 7.8 degrees.