McGraw Hill Glencoe Algebra 1, 2012
MH
McGraw Hill Glencoe Algebra 1, 2012 View details
3. Solving Multi-Step Inequalities
Continue to next subchapter

Exercise 26 Page 301

The phrase is no more than can be expressed as ≤.

Example Variable: Let x represent the number.
Inequality: 10 ≤ 4(2x+3)
Solution Set: {x|x ≥ - 14}

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 is no more than can be expressed as ≤. This symbol will be in the middle of our expression. ... ≤... On the left-hand side of the inequality symbol, we will translate any verbal expression that comes before is no more than.

ten 10 On the right-hand side of the inequality symbol, we will translate any verbal expression that comes after is no more than. If we let x represent a number, we can form an algebraic expression. Note that x is an example variable — we can use any letter to represent it. 4times the sum of twice a number and three 4 ( 2 x + 3 ) Finally, we can bring these two expressions together to form the inequality. 10 ≤ 4(2x+3)

Solving the Inequality

Using the Properties of Inequality, we will solve the inequality by isolating the variable.
10 ≤ 4(2x+3)
10 ≤ 8x+12
- 2≤ 8x
- 2/8≤ x
- 1/4≤ x
x≥ - 1/4
This tells us that all values greater than or equal to - 14 satisfy the inequality. Let's write the solution set. {x|x≥ -1/4}

Checking Our Solution

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

x 10 ≤ 4 (2x+3) Evaluate
-1/2 10 ? ≤ 4(2( -1/2)+3) 10 ≰ 8
-1/4 10 ? ≤ 4(2( - 1/4)+3) 10 ≤ 10
-1/8 10 ? ≤ 4(2( - 1/8)+3) 10 ≤ 11

We can conclude that, as long as x is greater than or equal to - 14, the inequality is satisfied. This means the solution set we have found is correct.