Solve the Absolute Value Equation: |x+2| = |x-2|

Absolute Value Equations with Case Analysis

x+2=x2 |x+2|=|x-2|

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1

Understand the problem

x+2=x2 |x+2|=|x-2|

2

Step-by-step solution

To solve the equation x+2=x2 |x+2|=|x-2| , we begin by considering the properties of absolute values.

The statement A=B |A| = |B| implies two cases:

  • Case 1: A=B A = B
  • Case 2: A=B A = -B

For our problem, consider:

  • Case 1: x+2=x2 x + 2 = x - 2
  • Case 2: x+2=(x2) x + 2 = -(x - 2)

Let's solve each case:

  • Case 1: x+2=x2 x + 2 = x - 2
    Subtract x x from both sides: x+2x=x2x x + 2 - x = x - 2 - x Reduce to: 2=2 2 = -2 Since 22 2 \neq -2 , this case has no solution.
  • Case 2: x+2=(x2) x + 2 = -(x - 2)
    Expand the right-hand side: x+2=x+2 x + 2 = -x + 2 Add x x to both sides: x+x+2=2 x + x + 2 = 2 This simplifies to: 2x+2=2 2x + 2 = 2 Subtract 2 from both sides: 2x=0 2x = 0 Solve for x x : x=0 x = 0

Thus, the solution to x+2=x2 |x+2|=|x-2| is x=0 x = 0 . The correct answer is the choice: x=0 x = 0 .

3

Final Answer

x=0 x=0

Key Points to Remember

Essential concepts to master this topic
  • Rule: When |A| = |B|, consider both A = B and A = -B
  • Technique: For |x+2| = |x-2|, solve x+2 = x-2 and x+2 = -(x-2)
  • Check: Substitute x = 0: |0+2| = |0-2| becomes 2 = 2 ✓

Common Mistakes

Avoid these frequent errors
  • Only considering one case when solving absolute value equations
    Don't solve just x+2 = x-2 and stop = missing the real solution! Case 1 gives no solution (2 = -2), but Case 2 gives the answer. Always check both A = B and A = -B when solving |A| = |B|.

Practice Quiz

Test your knowledge with interactive questions

\( \left|-x\right|=10 \)

FAQ

Everything you need to know about this question

Why do I need to consider two cases for absolute value equations?

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The absolute value symbol means distance from zero, which is always positive. So |A| = |B| means two expressions have the same distance from zero - they could be equal (A = B) or opposite values (A = -B).

What if one of my cases gives no solution?

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That's completely normal! In this problem, Case 1 gives 2=2 2 = -2 , which is impossible. Just move on to Case 2 - sometimes only one case has a valid solution.

How do I know which case will give the real answer?

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You don't know ahead of time - that's why you must solve both cases! Sometimes both work, sometimes only one works, and sometimes neither works (no solution).

Can I solve this by graphing instead?

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Yes! Graph y=x+2 y = |x+2| and y=x2 y = |x-2| . The x-coordinate where the graphs intersect is your solution. For this problem, they cross at x = 0.

Why does Case 1 give 2 = -2?

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When you solve x+2=x2 x + 2 = x - 2 , subtracting x from both sides leaves 2=2 2 = -2 . This is a contradiction - it means no value of x can make this case true.

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