Question

If a and −a are numbers on the number line, which expression MUST give the distance between them? A) 0 B) a Eliminate C) |2a| D) |a|

Answer 1

If a and -a are numbers on the number line, expression/letter C, |2a| gives the distance between them.

For example, a = 1; -a = -1
1 and -1's distance is not 0. (A) It is certainly not (B) and (D) or 1, leaving (C) or |2 × 1 | = 2.
-1 + 2 = 1

Answer 2

The answer would be c because the absolute value of both numbers would be the distance between them