smaller than or equal to is represented by <=.
greater than or equal to is represented by >=.
<= is the same as:
<
-
>= is the same as:
>
-
not equal to is represented by <>
check the following link for reference on howw to draw number line and, as a bonus, how to use interval notation.
http://www.mathsisfun.com/sets/intervals.html
basically you will have a line that goes from -3 to 6
since your interval is -3 < x <= 6, then you have an open end at -3 and a clossed end at 6.
If I represent the closed end as [ or ] and the open end as ( or ), then your nuymber line would look like the following:
------------------------------------------------------------------------------
-4 -3 -2 -1 0 1 2 3 4 5 6 7
(-------------------------------------]
The reference tells you to use an open circle for ( and a close circle for ]
as long as your audience knows the symbols you are using, and what they mean, you can use just about anything to represent closed end or open end.
not that in interval notation, this would be shown as (-3,6].