pemdas (or bidmas or whatever you want to call it) doesn't provide an answer here, that's a common misconception. the question as it is stated is ambiguous.
and in any case, if it was written using actual notation and not weird asciified notation, it'd be either
6
--- (1 + 2)
2
or
6
------
2(1+2)
and there wouldn't be any ambiguity. the ambiguity comes from squishing the equation onto one line.
(i think)