Maybe you don't understand absolute value. If the number between the two
bars|| is positive or zero, just erase the bars.  If the number between 
the bars is negative, erase the bars AND the negative sign, making it a
positive number.  

Three of them -1, 7, and -7 are already simplified as a positive or negative
number.

Only two of them, |-6| and |8|, need to be simplified. So we simplify them:

|-6|=6,

|8|=8

We draw a number line, like this:

--------------------------------------------------------
-9 -8 -7 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9

Then we put them all on the number line

-------o-----------------o--------------------o--o--o---
-9 -8 -7 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9
       |                 |                    |     |
      -7                -1                  |-6| 7 |8|                        

Then we list them as they appear left to right

-7, -1, |-6|, 7, |8|

Edwin