Exercise 9 Page 288

To algebraically express a verbal inequality, we will need to translate the given information into mathematical symbols and operations.

Writing the Inequality

The phrase $\text{at}$ $\text{least}$ can be expressed with the symbol $\ge ,$ which will be at the center of our expression. On the left-hand side of the inequality symbol, we will translate any verbal expression that comes before the phrase $\text{is}$ $\text{at}$ $\text{least}.$ If we let $x$ represent a number, we can form this expression. On the right-hand side of the inequality symbol, we will translate any verbal expression that comes after $\text{is}$ $\text{at}$ $\text{least}.$ Finally, we can bring these two expressions together to form the inequality.

Solving the Inequality

Using the Properties of Inequality, we will solve the inequality by isolating the variable. This solution tells us that all values greater than or equal to $6$ will satisfy the inequality.

Checking Our Solution

We can check our solution by substituting a few arbitrary values into the inequality translated above. The value satisfies the inequality if the inequality remains true after substituting and simplifying.

$x$	$2x+4\ge 10+x$	Simplify
$5$	$2(5)+4\stackrel{?}{\ge }10+5$	$14\ngeqq 15$
$6$	$2(6)+4\stackrel{?}{\ge }10+6$	$16\ge 16$
$7$	$2(7)+4\stackrel{?}{\ge }10+7$	$18\ge 17$

We can conclude that as long as $x$ is greater than or equal to $6,$ the inequality is satisfied.