Afaik sqrt only returns positive numbers, but if you’re searching for X you should do more logic, as both -3 and 3 squared is 9, but sqrt(9) is just 3.
If I’m wrong please correct me, caz I don’t really know how to properly write this down in a proof, so I might be wrong here. :p
(ps: I fact checked with wolfram, but I still donno how to split the equation formally)