I will try to explain the way I see it. In my opinion, the issue is generated by how the formula is written.

If it's written as as 48/2(9+3), in my opinion that's 288.

Google PEMDAS or BIDMAS or BODMAS (they are the same thing, which explains the operation you should solve first)

If you do parentheses first that's 12, agree with you.

Then, you must solve the division 48/2 (=24), then multiply that by 12, you have 288. That's the sequence, as prescribed by PEMDAS

Now, I see that, with fractional notation, you would write that as:

__ 48 __

2(9+3)

In that way, you solve first the denominator completely resulting in 24, and they divide 48 into 24, resulting in 2.

Conclusion:

For the formula written as it was in the thread title applying PEMDAS convention, the result is 288.

If you write it as a fraction, the result would be 2, but it was not written that way.