The positions of a, B and C on the number axis are shown in the figure below, which is simplified as follows: 1. |a + B | + |b-c | - A + C | 2. |2a-b | + |a-3c | - B + 3C| ———————|———|—|————|———————→ c a 0 b

The positions of a, B and C on the number axis are shown in the figure below, which is simplified as follows: 1. |a + B | + |b-c | - A + C | 2. |2a-b | + |a-3c | - B + 3C| ———————|———|—|————|———————→ c a 0 b

1、
B is farther from the origin than a
|b|>|a|,b>0,a-a,a+b>0
|a+b|=a+b
b>c,b-c>0
a

The numbers a, B and C corresponding to points a, B and C on the number axis are not zero, and C is the midpoint of ab. | a + B | &# 173; &# 173; - | a &# 173; - 2C | + | b-2c | &# 173; '--
|A + B ‐ 2C | = 0, then the position of origin o is on the extension of B segment Ca on a segment AC, C segment BC and D segment CB

C is the midpoint of AB = > A + B = 2C
|a﹢b|­­-|a­-2c|﹢|b-2c|­‐|a﹢b‐2c|﹦0
=>|a﹢b|­­-|a­-2c|﹢|b-2c|­=0
=>|2c|-|b|+|a|=0
So, B, C are different from a
=>A correct