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For inequalities on a number line, what does it mean when a point is open or closed?
2 > p Observing the given inequality, we see that 2 is greater than all values of p. This means that the solution set lies to the left of 2 on a number line. Furthermore, the inequality symbol indicates that p=2 is not a solution, which we will mark with an open circle on the number line at 2.
Similar to an equation, an inequality is a mathematical statement that compares two quantities. Some inequalities indicate that the two quantities are not necessarily equal, while others are strictly never equal.
Symbol | Strict / Non-strict | Example | Meaning |
---|---|---|---|
< | Strict | x<1 | The variable x is less than 1. |
≤ | Non-strict | x+1 ≤ -3 | The algebraic expression x+1 is less than or equal to - 3. |
> | Strict | 2x-5 > 5 | The expression 2x-5 is greater than 5. |
≥ | Non-strict | x ≥ 2x+1 | The variable x is greater than or equal to the expression 2x+1. |
With an inequality, it is possible to compare any combination of two numbers, variables, numeric expressions, or algebraic expressions. As can be seen in the table, there are four different types of inequalities. There are several ways each inequality can be phrased.
Symbol | Key Phrases |
---|---|
< | & ∙ is less than & ∙ is fewer than |
> | & ∙ is greater than & ∙ is more than |
≤ | & ∙ is less than or equal to & ∙ is at most & ∙ is no more than |
≥ | & ∙ is greater than or equal to & ∙ is at least & ∙ is no less than |