McGraw Hill Glencoe Algebra 1, 2012
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McGraw Hill Glencoe Algebra 1, 2012 View details
1. Solving Inequalities by Addition and Subtraction
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Exercise 30 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 is more than can be expressed as >. This symbol will be at the center of our expression. ... >... We will translate any verbal expression that comes before is more than on the left-hand side of the inequality symbol. If we let n represent a number, we can form this expression.

twice a number 2 n On the right-hand side of the inequality symbol we will translate any verbal expression that comes after is more than. the sum of that number and 9 n + 9 Finally, we can bring these two expressions together to form the inequality. 2n>n+9

Solving the Inequality

Using the Properties of Inequality, we will solve the inequality by isolating the variable.
2n>n+9
n>9
This solution tells us that all values greater than 9 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.

n 2n>n+9 Simplify
8 2( 8)? > 8+9 16≯ 17
9 2( 9)? > 9+9 18≯ 18
10 2( 10)? > 10+9 20>19

We can conclude that as long as n is greater than 9, the inequality is satisfied.