Exercise 35 Page 288

We will first translate the given information into algebraic symbols and operations. Then, we will solve the inequality.

Writing the Inequality

We want to find the number of online teens that do not use the Internet at school. Let's call this value $n$. For simplicity, let's let this value be in millions of people. To help us find this value, we will use a few key phrases.

Verbal Expression	Algebraic Expression
More than	$>$
Number of teenagers that use the Internet	$21\text{ million}$
Number of teenagers that use the Internet at school	$16\text{ million}$
Millions of teenagers that do not use the Internet at school	$n$

Since the survey found that more than $21$ million people between the ages of $12$ and $17$ use the Internet and that about $16$ million said that they use the Internet at school, the variable $n$ would be more than the difference between $21$ million and $16$ million.

Solving the Inequality

To find how many millions of teens do not use the Internet at school, we will simplify the inequality we wrote. Let's write the solution set in set-builder notation. There are more than $5$ million students who do not use the Internet at school.