@barznjy I answered your question in the main site.

Plot[Flatten[(x /. # & /@ Solve[#, x, Reals]) & /@
   List @@ FullSimplify[
     RegionMember[
      RegionBoundary@
       ImplicitRegion[
        EuclideanDistance[{0, 0}, {x, y}] <= 1 ||
         EuclideanDistance[{1, 1/3}, {x, y}] <= 1, {x, y}], {x,
       y}], (x | y) \[Element] Reals]], {y, -1, 2}, Evaluated -> True,
  AspectRatio -> Automatic, PlotPoints -> 100]

Circles don't meet on v10.2. Is it a bug in RegionMember?

@Pickett data.stackexchange.com/mathematica/query/348909/…

Ehm, I think it's Solve...

@belisarius Ah, the data explorer can do stuff like that. It counts bounties as lost, but other than that looks alright, so I don't know why it's so different - but better trust it.

@Pickett Well, there is a note in Portuguese saying that it isn't "exact"

But it doesn't say where the problems are

@Verbeia thank you so much.

I'm 30k. Thank you, thank you for all the applause

throws rose petals