Math Problem Statement

solve |5x-8|>2x+1

Solution

To solve the inequality 5x8>2x+1|5x - 8| > 2x + 1, we need to break it into two cases since it involves an absolute value. The definition of absolute value leads to two scenarios: one where the expression inside the absolute value is positive and one where it is negative.

Case 1: 5x8>05x - 8 > 0

Here, 5x8=5x8|5x - 8| = 5x - 8, so the inequality becomes:

5x8>2x+15x - 8 > 2x + 1

Now, solve for xx:

5x2x>1+85x - 2x > 1 + 8

3x>93x > 9

x>3x > 3

Case 2: 5x8<05x - 8 < 0

In this case, 5x8=(5x8)=5x+8|5x - 8| = -(5x - 8) = -5x + 8, so the inequality becomes:

5x+8>2x+1-5x + 8 > 2x + 1

Now, solve for xx:

5x2x>18-5x - 2x > 1 - 8

7x>7-7x > -7

x<1(Remember to flip the inequality when dividing by a negative number)x < 1 \quad \text{(Remember to flip the inequality when dividing by a negative number)}

Combine the results:

  • From Case 1, we found x>3x > 3.
  • From Case 2, we found x<1x < 1.

Thus, the solution to the inequality 5x8>2x+1|5x - 8| > 2x + 1 is:

x<1orx>3x < 1 \quad \text{or} \quad x > 3

This can be written in interval notation as:

(,1)(3,)(-\infty, 1) \cup (3, \infty)

Would you like further details or clarifications on any of the steps?


Here are some related questions you might find interesting:

  1. How do you solve absolute value equations like x5=3|x - 5| = 3?
  2. What happens if the inequality is 5x82x+1|5x - 8| \leq 2x + 1?
  3. Can this method be applied to inequalities with more complex expressions inside the absolute value, like 2x+3>4x1|2x + 3| > 4x - 1?
  4. How do you graph absolute value inequalities on a number line?
  5. What is the importance of considering both positive and negative cases when solving absolute value inequalities?

Tip: Always remember to flip the inequality when dividing or multiplying by a negative number.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Inequalities

Formulas

|a| > b implies a > b or a < -b

Theorems

Definition of absolute value
Inequality solving principles

Suitable Grade Level

Grades 8-10