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ABSOLUTE VALUE

Absolute Value

Absolute Value of a number is its distance from zero on the number line. The absolute value of a number n is denoted by |n|.

More About Absolute Value

Absolute value function is a piecewise function and is written as f (x) = |x|, where f(x) ≥ 0 for all values of x
This means that f (x) = - x for x < 0="" or="" f="" (x)="x" for="" x="" ≥="">
Absolute Value Inequalities: For all real numbers x and y, y > 0
1. if |x| < y,then="" -y="">< x=""><>
2. if |x| > y, then x > y or x <>
Absolute Value Equation: It is an equation of the form |ax + b| = c

Examples of Absolute Value

Absolute Value: The absolute value of – 5 is 5, because – 5 is 5 units away from zero on the number line.
The absolute value of 6 is 6, because 6 is 6 units away from zero on the number line.
Absolute Value Function: y = |x| + 3
Absolute Value Inequalities: |m| > 5
Absolute Value Equation: |x - 3| = 6

Video Examples: Absolute Value 1
 

Solved Example on Absolute Value

Simplify the inequality |6 - x| - 3 > 2

Choices:

A. x < -="" 11="" or="" x=""> - 1
B. x > 11 or x <>
C. x < 11="" or="" x=""> 1
D. None of these

Correct Answer: B

Solution:

Step 1: |6 - x| - 3 > 2 = |6 - x|> 5
Step 2: = - 5 > 6 - x > 5
Step 3: = - 5 - 6 > - x > 5 - 6
Step 4: = - 11 > - x > - 1
Step 5: = 11 < x=""><>
Step 6: = x > 11 or x <>

Quick Summary

  • Absolute value is always non-negative.
  • It represents the distance from zero.
  • |x| = |-x| for any real number x.
\[ |x| = \begin{cases} x, & \text{if } x \geq 0 \\ -x, & \text{if } x < 0 \end{cases} \]

🍎 Teacher Insights

Use visual aids like the number line to illustrate the concept of distance from zero. Emphasize the piecewise nature of the absolute value function when solving equations and inequalities. Encourage students to check their solutions.

🎓 Prerequisites

  • Number Line
  • Integers
  • Inequalities

Check Your Knowledge

Q1: What is the value of |-9|?

Q2: Solve for x: |x| = 5

Frequently Asked Questions

Q: What is the absolute value of -7?
A: The absolute value of -7 is 7, because -7 is 7 units away from zero.

Q: Can the absolute value of a number be negative?
A: No, the absolute value of a number is always non-negative.

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