Answer
There is a parenthesis when the value is not included. There is a bracket when the value is included.
Work Step by Step
For example, if the inequality is $x\lt 10$, there will be a parenthesis after the 10.
$(-\infty, 10)$
If the inequality is $x\leq 10$, there will be a bracket after the 10.
$(-\infty, 10]$
