Absolute Value & Radical Equations

Solve equations containing absolute values or square roots, split into cases and check for extraneous solutions. Try “solve |2x − 5| = 9”.

Try an example:

How the Absolute Value & Radical Equations works

  1. For |A| = k, solve the two cases A = k and A = −k.
  2. For a radical, isolate the root, then square both sides.
  3. Always substitute back: squaring can introduce extraneous solutions.

Frequently asked questions

What is an extraneous solution?

A value that satisfies the transformed equation but not the original one, so it must be discarded.

Can an absolute value equal a negative number?

No. |A| is never negative, so |A| = −3 has no solution.

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