Math Problem Statement

|3x+9|>7

Solution

We need to solve the inequality 3x+9>7|3x + 9| > 7. Here's how we can approach it step-by-step:

Step 1: Set up two cases for the absolute value.

For any absolute value inequality A>B|A| > B, where B>0B > 0, the inequality splits into two cases:

  1. A>BA > B
  2. A<BA < -B

In this case, A=3x+9A = 3x + 9 and B=7B = 7. Therefore, we get the following two inequalities:

  1. 3x+9>73x + 9 > 7
  2. 3x+9<73x + 9 < -7

Step 2: Solve each inequality.

Case 1: 3x+9>73x + 9 > 7

3x>793x > 7 - 9 3x>23x > -2 x>23x > -\frac{2}{3}

Case 2: 3x+9<73x + 9 < -7

3x<793x < -7 - 9 3x<163x < -16 x<163x < -\frac{16}{3}


Step 3: Combine the solutions.

The solution to 3x+9>7|3x + 9| > 7 is the union of the two intervals:

x<163orx>23x < -\frac{16}{3} \quad \text{or} \quad x > -\frac{2}{3}

In interval notation, the solution is:

(,163)(23,)(-\infty, -\frac{16}{3}) \cup (-\frac{2}{3}, \infty)


Would you like further details or have any questions?

Here are 5 related questions:

  1. How do you solve absolute value inequalities involving \leq or \geq?
  2. How does the solution change if the inequality was 3x+9<7|3x + 9| < 7?
  3. What is the general rule for splitting absolute value inequalities?
  4. How can you graph the solution on a number line?
  5. What happens if the inequality is A>B|A| > -B with B<0B < 0?

Tip: Always check if the absolute value expression can be simplified before solving the inequality.

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Inequalities

Formulas

|A| > B splits into A > B or A < -B

Theorems

Absolute Value Inequality Property

Suitable Grade Level

Grades 8-10