which of the following expressions reperesents the distance between -13 and -4 on a number line?

Answer:
Step-by-step explanation:
You've shared only possible answers a and c. What about b and d?
Answer a) is correct. The second - sign represents the difference between -13 and -4 (which is 7, by the way). -13 - (-4) works out to -13 + 4 = -9, and the absolute value of that is |-9|, or 9, the distance between -13 and -4.
Answer:
It is a.
Step-by-step explanation:
The distance is | -13 - (-4)|
= |-9|
= 9