The correct answer is 9 btw.
I assume the second some how thinks 2(1+2)≡2/(1+2). I have never come across this notation before (it only happens with the ÷ sign) but it could be a recognised notation?
It depends on how you solve it. If you follow order of operations (PEMDAS), the answer is one. If you solve it from left to right, the answer is nine. It's ambiguous at best.