That's retarded. BEDMAS = PEMDAS. Division doesn't come before multiplication and vice versa. They're done at the same time from left to right and there's absolutely no difference between what the two mean- the acronyms may be different, but it's still the same OOO.
Also, that's not a troll. At all. That's called you putting up a math problem and someone getting it wrong, then you telling them they're wrong. It's simple logic. Trolling involves inciting anger through the use of illogical bait and is followed up with arbitrary rebuttals.
This is utterly flawed. 48 / 2(9+3) is:
48 / 2 (12)
48 / 2 = 24
24 * 12 = 288
288 <> 2
Just because the equation says it does not mean it's true. Yes, that's working it out correctly; that doesn't magically mean that 288 = 2. If you put that as the answer to this question on a math test anywhere, you would most likely get slapped upside the head.
Trolling involves the use of subjective logic which can more often than not be proven wrong; but using math, which is a completely objective system, is about the stupidest way to try to 'troll', because there's always a clear correct answer. In this case, "no solution." My guess is that your "best troll ever" actually went something like this:
Now get out of my Off-Topic. Come back when you figure out how to use that thing called a "brain" which is lodged in your skull.