Under Under What Circumstances Would A Quadratic Inequality Have A Solution Set That Is A Closed Interval?

Under what circumstances would a quadratic inequality have a solution set that is a closed interval? - under

Can anyone help me with this? The teacher was not in the class, and we want to do homework, and I'm lost. Everything would be great ... Thank you very much


Under what circumstances, a second degree inequality, a number of solutions have is a closed interval? Under what circumstances, a second degree inequality have a number of vacuum solutions? Give an example for each situation.