Answer:
12
Explanation:
A midpoint of a line means that each segment connecting from the midpoint to an end is equal. For this problem, this means that AB = BC, as B is the midpoint, and A and B are the ends. Therefore, we can say that:
AB = BC
2x + 6 = 5x - 3
add 3 to both sides
2x + 9 = 5x
subtract 2x from both sides
9 = 3x
divide both sides by 3
3 = x
Plugging 3=x into AB, this means that 2(3) + 6 = AB = 12