In an inequality
If you have
x >3
the solution is all real numbers greater than 3 (3, infinite)
NOTE that the number 3 is not included in the solution
that means ----> is an open circle at x=3
x≥3
the solution is all real numbers greater than or equal to 3 [3, infinite)
NOTE that the number 3 is included in the solution
that means ----> closed circle at x=3
we have the inequality
x + 19> 31
solve for x
x > 31-19
x > 12
the solution is the interval (12, infinite)
All real numbers greater than 12
In a number line, the solution is the shaded area at the right of x=12 (open circle)
see the figure below