In case of inequalities we have following two rules.
Rule 1:
If we have just greater than > or less than < sign , then we would use open cirlce.
An open dot means the function has no definition at the specific point
Greater Than, >, and Less Than, <, mean the solution does NOT contain the number
Rule 2:
For inequalities. Greater Than or Equal TO, >, and Less Than or Equal TO, <, mean the solution does contain the number.
So in that case we will use closed circle.
Hope that helps.