isn't that division sign I only saw Americans use written like this (÷) means it's a fraction? so it's 6÷2, since the divisor (or what is it called in english, the bottom half of the fraction) isn't in parenthesis, so it would be foolish to put the whole 2(1+2) down there, there's no reason for that.
so it's (6/2)*(1+2) which is 3*3 = 9.
the other way around would be 6÷(2(1+2)) if the whole expression is in the divisor and than that's 1.
tho I'm not really proficient in math, I have eventually failed it in university, but if I remember my teachers correctly, this should be the way. but again, where I live, we never use the ÷ sign, only in elementary school where we divide on paper. instead we use the fraction form, and with that, these kind of seemingly ambiguous expressions doesn't exist.