|x| = |-x|

Definition

The equation |x| = |-x| expresses the property of absolute value, indicating that the absolute value of a number is equal to the absolute value of its negation. This property is fundamental in understanding how distance works on the real number line, as it reflects that both a number and its opposite are the same distance from zero. This concept helps in solving equations and inequalities involving absolute values, as well as in graphical representations of these values on a number line.

5 Must Know Facts For Your Next Test

1. The property |x| = |-x| holds true for all real numbers, demonstrating the symmetry of the absolute value function around the origin.
2. Graphically, the absolute value function creates a 'V' shape when plotted, confirming that both x and -x yield the same y-value for any x.
3. This property is especially useful when solving equations that involve absolute values, as it allows for simplification by considering positive and negative cases.
4. In real-world applications, such as measuring distances, this property ensures that direction does not affect the overall measurement.
5. Understanding this equation can aid in deeper concepts like piecewise functions, where absolute value can define different behaviors based on whether the input is positive or negative.

Review Questions

• How does the equation |x| = |-x| reflect properties of symmetry in mathematics?
  • The equation |x| = |-x| illustrates symmetry because it shows that for any real number x, its absolute value remains unchanged regardless of its sign. This means that both positive and negative values yield the same result when measuring distance from zero. Such symmetry is crucial in mathematical concepts like graphing functions, as it indicates that if a point lies on one side of the origin, its negation will be equidistant from the origin on the opposite side.
• How can you use the property |x| = |-x| to simplify solving an absolute value equation like |3x - 2| = 5?
  • To solve an equation like |3x - 2| = 5 using |x| = |-x|, you can set up two separate equations: 3x - 2 = 5 and 3x - 2 = -5. This allows you to solve for x in both cases, giving solutions for when 3x - 2 equals a positive and a negative result. By leveraging this property, you can effectively capture all potential solutions related to both directions on the number line.
• Evaluate how the concept of |x| = |-x| applies to real-world scenarios involving distance measurement.
  • In real-world contexts, such as measuring distances in navigation or physics, the concept of |x| = |-x| reinforces that distance is always a non-negative quantity. For example, if you're calculating how far two points are from a reference point, it doesn’t matter if you're moving forward or backward; the distance remains constant. This understanding helps in various applications, such as ensuring accurate readings in GPS technology or interpreting data in scientific research where direction may vary but magnitude matters.

Related terms

Absolute Value: The absolute value of a number is its distance from zero on the real number line, regardless of direction.

Distance Formula: A mathematical formula used to calculate the distance between two points on a number line or in coordinate geometry.

Negation: The negation of a number is the value that is opposite in sign; for example, the negation of 5 is -5.