Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
1. Inequalities and Their Graphs
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Exercise 3 Page 167

For inequalities on a number line, what does it mean when a point is open or closed?

Practice makes perfect
We want to find the graph of the given inequality. To graph an inequality on a number line, we need to make note of two things. The first thing is the direction of the inequality and the second thing is whether it is strict. Let's consider the given inequality.

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.

Extra

More About Inequalities

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