Question 594645
Squaring both sides essentially weakens a statement. For example, suppose that 


*[tex \LARGE x = 1]


Squaring both sides yields


*[tex \LARGE x^2 = 1]


However the second equation is not equivalent to the first one, as x could equal 1 or -1. You can square both sides when dealing with "if and only if" relations, for example, if you know that x must be positive.