You can
put this solution on YOUR website!
<==================●------------------------------------
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
or
<==================]------------------------------------
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
Depending on your book, it's either a darkened circle at
-3 or a right bracket, and the line to the left of it is
darkened.
Edwin