Math Problem Statement

Solve the inequalities and absolute value problems: 1. Solve and graph the solution set for |2x + 7| < 11. 2. Solve and graph the solution set for |x + 1| ≥ 2. 3. Solve for x: |2x - 5| = 8.

Solution

Here’s a detailed breakdown of the problems shown in the image:


Problem 1

Solve the inequality and graph the solution set:
2x+7<11|2x + 7| < 11

Solution Steps

The absolute value inequality A<B|A| < B can be rewritten as:
B<A<B-B < A < B
Here A=2x+7A = 2x + 7 and B=11B = 11, so:
11<2x+7<11-11 < 2x + 7 < 11

  1. Subtract 7 from all parts:
    117<2x<117-11 - 7 < 2x < 11 - 7
    18<2x<4-18 < 2x < 4

  2. Divide through by 2:
    9<x<2-9 < x < 2

Solution in Interval Notation

x(9,2)x \in (-9, 2)

Graph

On a number line:

  • Open circles at x=9x = -9 and x=2x = 2.
  • Shade the region between these points.

Problem 2

Solve the inequality and graph the solution set:
x+12|x + 1| \geq 2

Solution Steps

The absolute value inequality AB|A| \geq B can be rewritten as two cases:
ABorABA \geq B \quad \text{or} \quad A \leq -B

Here A=x+1A = x + 1 and B=2B = 2, so:

  1. First case:
    x+12    x1x + 1 \geq 2 \quad \implies \quad x \geq 1

  2. Second case:
    x+12    x3x + 1 \leq -2 \quad \implies \quad x \leq -3

Solution in Interval Notation

x(,3][1,)x \in (-\infty, -3] \cup [1, \infty)

Graph

On a number line:

  • Closed circle at x=3x = -3 and x=1x = 1.
  • Shade the regions x3x \leq -3 and x1x \geq 1.

Problem 3

Solve for xx:
2x5=8|2x - 5| = 8

Solution Steps

The absolute value equation A=B|A| = B can be rewritten as two cases:
A=BorA=BA = B \quad \text{or} \quad A = -B

Here A=2x5A = 2x - 5 and B=8B = 8, so:

  1. First case:
    2x5=8    2x=13    x=132=6.52x - 5 = 8 \quad \implies \quad 2x = 13 \quad \implies \quad x = \frac{13}{2} = 6.5

  2. Second case:
    2x5=8    2x=3    x=32=1.52x - 5 = -8 \quad \implies \quad 2x = -3 \quad \implies \quad x = -\frac{3}{2} = -1.5

Solution

x=6.5orx=1.5x = 6.5 \quad \text{or} \quad x = -1.5


Summary

  1. Problem 1: x(9,2)x \in (-9, 2)
  2. Problem 2: x(,3][1,)x \in (-\infty, -3] \cup [1, \infty)
  3. Problem 3: x=6.5x = 6.5 or x=1.5x = -1.5

Would you like me to explain any part further or graph these solutions for clarity?


Related Questions:

  1. How do you solve inequalities involving absolute values?
  2. What is the difference between A<B|A| < B and A>B|A| > B?
  3. How can interval notation be converted to graphical representation?
  4. Why do absolute value inequalities produce two cases?
  5. How do we check if a solution is valid in an absolute value equation?

Tip: Always check absolute value solutions by substituting them back into the original equation to ensure they satisfy the conditions.

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Math Problem Analysis

Mathematical Concepts

Absolute Value Inequalities
Interval Notation
Graphing Solutions

Formulas

|A| < B → -B < A < B
|A| > B → A > B or A < -B
|A| = B → A = B or A = -B

Theorems

Properties of Absolute Values
Solution of Linear Inequalities

Suitable Grade Level

Grades 9-11