|6 - 3*(8 - 2)| 

First we do all the operations with the numbers in the absolute values, that is:

6 - 3*(8 - 2) = 6 - 3*6 = 6 - 18 = -12

Then we calculate absolute value of "-12".

Since the definition for absolute value is:

|A| = A, if A>=0

|A| = -A, if A<0 

In our case we have A = -12 and -12<0 so

|-12| = - (-12) = 12