Solve |x| = 7: Finding Values in an Absolute Value Equation

Absolute Value Equations with Two Solutions

x=7 \left|x\right|=7

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Step-by-step written solution

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1

Understand the problem

x=7 \left|x\right|=7

2

Step-by-step solution

The equation is x=7 \left|x\right|=7 , which means that the absolute value of x x is 7. Therefore, x x could be 7 or -7. Thus, the solutions are x=7 x=7 and x=7 x=-7 .

3

Final Answer

x=7,x=7 x=-7, x=7

Key Points to Remember

Essential concepts to master this topic
  • Definition: Absolute value represents distance from zero on number line
  • Technique: x=7 |x| = 7 means x = 7 or x = -7
  • Check: Verify 7=7 |7| = 7 and 7=7 |-7| = 7 both equal 7 ✓

Common Mistakes

Avoid these frequent errors
  • Finding only one solution instead of both
    Don't solve x=7 |x| = 7 as just x = 7! This misses half the solutions because absolute value equations typically have two answers. Always consider both the positive and negative values that give the same absolute value.

Practice Quiz

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

FAQ

Everything you need to know about this question

Why does |x| = 7 have two answers?

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Because absolute value measures distance from zero! Both 7 and -7 are exactly 7 units away from zero on the number line, so both make x=7 |x| = 7 true.

How do I know when an absolute value equation has two solutions?

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When the absolute value equals a positive number, there are always two solutions. If it equals zero, there's one solution. If it equals a negative number, there are no solutions.

What if I only find x = 7 as my answer?

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You're missing half the solution! Remember that two different numbers can have the same absolute value. Always ask yourself: "What negative number also has this absolute value?"

How do I check my answers?

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Substitute each solution back into the original equation: 7=7 |7| = 7 ✓ and 7=7 |-7| = 7 ✓. Both should give you the same result as the right side.

Can absolute value equations have no solutions?

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Yes! If you get something like x=5 |x| = -5 , there are no solutions because absolute values are never negative. Distance can't be negative!

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