Definition of

Extraneous Root

A solution to an equation that SEEMS to be right, but when we check it (by substituting it into the original equation) turns out NOT to be right.

Example: you have an equation and after some work come up with two roots (where it equals zero) "a" and "b". When you put "a" into the original equation it becomes zero, but when you put in "b" it doesn't. So "b" is an extraneous root.

This often happens when we square both sides during our solution.
See: Root

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