[grateful]

Of course x=2. You took the 2 and replaced it with x. Why would you set the equation equal to 288 if it was not the answer?

48/2(9+3) = x
48(9+3) = 2x
48*12 = 2x
576 = 2x
288 = x

[grateful]

Or, this, doing parens first following standard order of operations.

48/2(9+3) = x
48/2(12) = x
48*12 = 2x
576 = 2x
288 = x

[Ironfocus]

Where did the division go in your step 2? Should it not be 48/(9+3)=2x?

I tested both equations for the two suggested answers of 2 and 288, look more closely.