Sometimes true, always true, or never true and why: a square root function has two x-intercepts?

A function is any process that gives a single output value for each qualified input value. Square root is not a function, since every input value gives two outputs, plus and minus. So the question is not valid.

Nevertheless, we can pretend that square root is a function. It looks like this: www.wolframalpha.com/input/?i=plot+y+%3D+%E2%88%9Ax