Math Problem Statement

|9x + 7| < 4

Solution

The inequality presented in the image is:

9x+7<4|9x + 7| < 4

To solve this absolute value inequality, we follow these steps:

Step 1: Remove the absolute value by setting up two inequalities

The expression A<B|A| < B means that B<A<B-B < A < B. Therefore, we can write:

4<9x+7<4-4 < 9x + 7 < 4

Step 2: Solve the compound inequality

We now solve the inequality in two parts.

Part 1: Solve 4<9x+7-4 < 9x + 7

  • Subtract 7 from both sides: 47<9x-4 - 7 < 9x 11<9x-11 < 9x
  • Divide by 9: 119<x\frac{-11}{9} < x x>119x > \frac{-11}{9}

Part 2: Solve 9x+7<49x + 7 < 4

  • Subtract 7 from both sides: 9x<479x < 4 - 7 9x<39x < -3
  • Divide by 9: x<39x < \frac{-3}{9} x<13x < \frac{-1}{3}

Step 3: Combine the two results

We have: 119<x<13\frac{-11}{9} < x < \frac{-1}{3}

Thus, the solution is: x(119,13)x \in \left( \frac{-11}{9}, \frac{-1}{3} \right)

Would you like a more detailed explanation of any step or have any other questions?

Here are 5 related questions:

  1. How do you solve absolute value inequalities when the sign is "greater than" (>)?
  2. What happens if you divide an inequality by a negative number?
  3. How do you graph inequalities on a number line?
  4. What are the differences between solving equations and inequalities?
  5. How would this solution change if the inequality were 9x+74|9x + 7| \leq 4?

Tip: When dealing with absolute values in inequalities, always remember that they split into two inequalities, one positive and one negative.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Inequalities

Formulas

|A| < B implies -B < A < B

Theorems

Absolute Value Theorem

Suitable Grade Level

Grades 8-10