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 9 Page 288

The phrase at least can be expressed as ≥.

Example Variable: x
Inequality: 2x+4≥ x+10
Solution Set: x≥ 6

Practice makes perfect

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

Writing the Inequality

The phrase at least can be expressed with the symbol ≥, 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 is at least. If we let x represent a number, we can form this expression.

twice a number increased by4 2 x + 4 On the right-hand side of the inequality symbol, we will translate any verbal expression that comes after is at least. 10more than the number x + 10 Finally, we can bring these two expressions together to form the inequality. 2x+4≥ x+10

Solving the Inequality

Using the Properties of Inequality, we will solve the inequality by isolating the variable.
2x+4≥ 10+x
x+4≥ 10
x≥ 6
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≥ 10+x Simplify
5 2( 5)+4? ≥ 10+ 5 14≱ 15
6 2( 6)+4? ≥ 10+ 6 16≥ 16
7 2( 7)+4? ≥ 10+ 7 18≥ 17

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