Solving Polynomial Inequalities and giving solution set in interval notation

In this example problem, we solve an already factored polynomial inequality to determine the intervals where the function will be greater than zero. The same process can be utilized for a similar problem where the function would be less than, less than or equal to, or greater than or equal to zero.

If there were a negative constant in front that was multiplied, that would change the positive/negative sign for each interval and our solution sets would be reversed.

[rociocamargo]

Why is it a closed dot instead of open