Open Sentences

Open Sentences in Algebra

Yes, sentences are not only used in English class, but also in Math! In algebra a sentence contains numbers, variables, operations and either an equal sign (=) or an inequality symbol.

A sentence that contains an equal sign (=) is called an equation. If a sentence is not an equation, then it is an inequality. Take a look at the following mathematical symbols for their corresponding meanings:

math symbols chart

An open sentence is a sentence that contains one or more variables that may be true or false depending on what values you substitute for the variables.

Open Sentences Examples

open sentences

As you discovered in the example above, the equations (open sentences with an equal sign) that we will study in this unit (linear equations) only have one solution, or one value for the variable that will make the sentence true.

Let's take a look at how you might find a solution for a sentence that is an equation (with an equal sign).

Solutions to Open Sentences

open sentence example

Ok, so that's not too hard. You need to have great mental math skills to find the solution to open sentences.

A sentence that is an inequality, may have many values for the variable that make the sentence true. Take a look:

Open Sentences with Inequality Symbols

open sentence for inequality

As you can see, there are many solutions when working with inequalities. We can express all of these solutions by using the inequality symbol in our answer.

If your mental math skills are not up to par, then you may have trouble finding solutions for these math sentences. When you use integers in math sentences, then finding the solutions can be really tough. Therefore, you may want to check out our lessons on solving equations.

It's best to start with the lesson on solving addition equations.

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