Math Problem Statement

Solve the inequality |5x + 1/2 - 4| < 8 and determine the solution set.

Solution

The inequality given in the image is:

5x+124<8|5x + \frac{1}{2} - 4| < 8

We need to solve this absolute value inequality step by step.

Step 1: Simplify the expression inside the absolute value.

5x+1245x + \frac{1}{2} - 4

Convert 4-4 into a fraction with denominator 2:

5x+1282=5x725x + \frac{1}{2} - \frac{8}{2} = 5x - \frac{7}{2}

So, the inequality becomes:

5x72<8|5x - \frac{7}{2}| < 8

Step 2: Remove the absolute value by writing two inequalities.

When we solve absolute value inequalities, we have two cases:

  1. 5x72<85x - \frac{7}{2} < 8
  2. (5x72)<8-(5x - \frac{7}{2}) < 8 (or equivalently 5x72>85x - \frac{7}{2} > -8)

Step 3: Solve each inequality separately.

Case 1: Solve 5x72<85x - \frac{7}{2} < 8

Add 72\frac{7}{2} to both sides:

5x<8+725x < 8 + \frac{7}{2}

Convert 8 into a fraction:

5x<162+72=2325x < \frac{16}{2} + \frac{7}{2} = \frac{23}{2}

Now, divide both sides by 5:

x<2310x < \frac{23}{10}

Case 2: Solve 5x72>85x - \frac{7}{2} > -8

Add 72\frac{7}{2} to both sides:

5x>8+725x > -8 + \frac{7}{2}

Convert 8-8 into a fraction:

5x>162+72=925x > -\frac{16}{2} + \frac{7}{2} = -\frac{9}{2}

Now, divide both sides by 5:

x>910x > -\frac{9}{10}

Step 4: Combine the results.

The solution to the inequality is:

910<x<2310-\frac{9}{10} < x < \frac{23}{10}

Final Answer:

The solution set is:

(910,2310)(-\frac{9}{10}, \frac{23}{10})

Thus, the correct choice is A, and the solution set in interval notation is (910,2310)\left( -\frac{9}{10}, \frac{23}{10} \right).


Would you like more details or have any questions?

Here are 5 follow-up questions:

  1. How do you handle absolute value inequalities that involve "greater than" instead of "less than"?
  2. What happens if you add or subtract a constant inside the absolute value?
  3. How can you represent the solution to inequalities using a number line?
  4. What is the difference between strict inequalities (like "<") and non-strict ones (like "≤")?
  5. How does multiplying or dividing by a negative number affect inequalities?

Tip: When solving inequalities, be careful with signs, especially when multiplying or dividing by negative numbers, as this reverses the inequality.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Inequalities

Formulas

Absolute value inequality |A| < B

Theorems

Properties of Absolute Value Inequalities

Suitable Grade Level

Grades 9-11