Changes

==Two square roots ==

==Two square roots ==

All numbers other than zero and negative numbers have two square roots that differ by a factor of -1:

All numbers other than zero have two square roots that differ by a factor of -1:

:<math>3 \cdot 3 = 9</math> and <math>-3 \cdot -3 = 9</math>

:<math>3 \cdot 3 = 9</math> and <math>-3 \cdot -3 = 9</math>