Yesterday, the temperature in a city dropped from 9°C to –9°C, as shown below.
The expression 9 + (–18) represents the final temperature. Which of the following is an equivalent way to describe this temperature?
|–18| degrees in a negative direction from 9 degrees
|–18| degrees in a positive direction from 9 degrees
|–9| degrees in a negative direction from 9 degrees
|–9| degrees in a positive direction from 9 degrees