It's better to swap them so the numbers will go from smallest
to largest,

          

Draw the number line graph:

<============☻-----------☺=============================>
-9 -8 -7 -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9

    

Interval notation is just an abbreviation for the graph on a
number line.

If the graph goes all the way to the left, put  
     on the left end of the
interval notation

If the graph goes all the way to the right, put
                            on the right end
of the interval notation

Edwin