Final answer:
The number line that shows -9 and its opposite 9 is labeled A) P: -24, -12, 0, 12, 24, as it includes both -9 and 9, which are opposites on a number line.
Step-by-step explanation:
To find which number line shows -9 and its opposite, we must understand that the opposite of a number is its additive inverse, meaning the number that, when added to the original number, equals zero. Looking at options A through D, we know that the number line must include both -9 and 9. The only number line that has both -9 and its opposite, 9, is option A) P: -24, -12, 0, 12, 24. None of the other number lines include the number 9.