Now  can be written as 

Now you have



Reverse these:



Now you can write these together as a continued inequality
like this:



That says x is between -6 and 9, INclusive of -6,
but EXclusive of 9, so on a number line the graph is

-------@============================================o---------
-8 -7 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10 11 12

Notice that there is a closed circle at -6 and an open circle
at 9.  The interval notation is an abbreviation of the above
graph.  The left endpoint is -6 and the right endpoint is 9,
so the interval notation is 

         [-6,9)

The bracket "[" on the left next to the -6 indicates that the -6
is included, the parentheses ")" on the right indicates that the
9 is NOT included. 

Edwin