Lesson Summary: By the end of this lesson, one should be able to use sign diagrams to solve polynomial inequalities. One should know that when one has an inequality sign that is less or greater than or equal to, one must draw closed circles, and if the inequality sign is less or greater than than, one must  draw open circle. If there is a closed circle then use brackets in the solution, and if there is an open circle, use parenthesis in the solution.