Algebra/Square Root is Positive

Square Root Is Not Negative
We often say that $$\sqrt{x}$$ is the positive number, which when squared is equal to $$x$$. If $$x>0$$ this is perfectly correct, but if $$x = 0$$ then $$\sqrt{x} = \sqrt{0} = 0 $$ which is not positive. So to be technically correct (which is part of the fun of math) we should say that $$\sqrt{x}$$ is the non-negative number, which when squared is equal to $$x$$.

If it is needed to express that a square root may be both positive and negative, you will see $$\plusmn \sqrt{x}$$.