Module 2: Lesson 3

 

Are You Ready?

2. Extraneous roots are solutions that appear to be correct but do not satisfy the initial restrictions on the variable.
   
   In the case of equations involving square roots, it is usually necessary to square both sides of the equation in order to solve the equation. Squaring both sides, however, removes the restrictions—that is, that the value under the square root sign not be negative. It then becomes necessary to check your solution(s) to ensure it is not extraneous. You can do this either by substituting your answer back into the original equation or by determining restrictions.

© 2012 Alberta Education