Inequalities on number line and Interval Notations!! Compound Inequalities Pre-Calculus Algebra Open Circle - Parentheses (Point not included) Closed circle - Brackets (Point included) -~-~~-~~~-~~-~- Please watch: "Limit of Trigonometric functions at Infinity and non zero values" https://www.youtube.com/watch?v=q6APL9H6bV0 -~-~~-~~~-~~-~-