...The OP eqn is a classic example of math notation ambiguity.
I never took a course in Classical Math Notation Ambiguity. What's another classic example?
mixing 3rd grade symboligy
You claim to remember your 3rd grade "symbiology"? But you can't remember your 8th grade basic algebra. That's a statement, not a question island911. If it was a question it would be rhetorical.
...Now had the eqn been 48 ÷ 2 x (9+3)
It was. You just added 'x', which is superfluous...and doesn't change a thing. If you remembered/understood your 8th grade beginning algebra you'd know that.
...then yeah, the L/R-rule-nazis
* would have an easy 288 win.
You seem to have a nasty psychological quirk that impels you to call people Nazis - not nice island911 (especially since you 'claim' to own a Porsche).
"an easy 288 win" That's amusing; you see mathematics as competitive, eh? You and doug crack me up (doug apparently sees math as a riddle).
. . .And for you rules-nazis; consider that if mathematical notation/syntax is so perfect then why are there SO MANY different symbols for say, multiplication? ( x * (dot) implies multiplication against a bracket.)
Gee whiz island911, there ya go again (Reagan, dontcha love it?), calling people Nazis, just because ya get all confused and irate about "SO MANY different symbols". Are you going to quote GWBush now and say, "This is hard!"?
Again, math notation is just that -
notation. ...a tool to an end.
Of course it is. Who's saying it isn't? Are you just stubbornly being...a tool to the end?
Like it or not, math notation is not some fixed, unmoving set of logical perfection. It has a history. It has evolved. It does evolve. (shocking, I know)
Math notation doesn't 'evolve'. That's a silly notion. Conventions regarding its use may differ from discipline to discipline and by preference, but the notation doesn't change meaning. Ask an 8th grade algebra teacher, or masraum or stign or Bill Verburg et al...unless you think you're smarter and more knowledgeable than they are. THAT would be funny.
To the current.. people use brackets, braces and grouping extensively, because the whole L/R rule is simply not a reasonable convention when solving large eqn's.
So...you just use the parts you feel like using? Thats how you came up with the answer '2', right?
Again, the OP eqn was
intentionally set to pit a third-grade math rule against a (math-working) grouping method.
That's really goofy island911.
How about 1/ 2X .. 1÷2X
You think that they are not identical, right? Or they confuse you?
... what about -3
2 ...is that 9? ...or -9?
Anyone who has a grasp of 8th grade algebra knows it's -9. Does that confuse you too?
Oh what did the writer mean? 
That's the crux of your problem island911; if you were 8th grade algebra proficient the goofy question "what does the writer mean?" wouldn't even enter your mind. You'd just solve the equation.
*just to add a dash of thread-kill.
.
You've obviously failed at thread-kill also.
So, what now? Wait for you to come back and call me a Nazi in clown shoes?