Equations with Absolute Values
This page introduces the concept of absolute value and its application in equations. It covers the first two types of equations with absolute values and provides detailed examples of how to solve them.
Definition: The absolute value (or modulus) of a number is its non-negative value without regard to its sign.
Highlight: In equations with absolute values, the unknown variable is contained within the absolute value symbols.
First Type of Equations: |A(x)| = K
For equations of the form |A(x)| = K, the solution method depends on the value of K:
- If K > 0, then A(x) = ±K
- If K = 0, then A(x) = 0
- If K < 0, there is no real solution
Example: Solve |x - 1| = 6
Solution: x - 1 = 6 or x - 1 = -6
x = 7 or x = -5
Therefore, S = {-5, 7}
Second Type of Equations: |A(x)| = B(x)
For equations of this type, we set up a system of equations:
{A(x) = B(x)
{A(x) = -B(x)
Example: Solve |x² + 5| = 2x
Solution: Set up the system:
{x² + 5 = 2x
{x² + 5 = -2x
Solve each equation to find S = {-5, 2}
The page concludes with a note that for x ≥ 0, |x| = x, and for x < 0, |x| = -x, which is crucial for understanding the behavior of absolute value functions.