Answer:
See below.
Step-by-step explanation:
a.
O is the origin, so its abscissa is 0. O: 0
The only point 4 units from O is A, so A: 4
Point C has a positive abscissa like A.
Points B and C have opposite abscissas. The only opposites are -3 and 3, but C is positive, and B is negative.
B: -3
C: 3
D: -4.5
E: -6
M = (4 + (-6))/2 = -1. M: -1
b.
OB = |0 - (-3)| = |3| = 3
DA = |-4.5 - 4| = |-8.5| = 8.5
