I've seen several math polls on facebook over the last year or two, but this is definitely the most confusing example. From a meta-math standpoint this is just bad ergonomics. It's the equivalent of putting handles on a push-only door and wondering why people hurt themselves trying to pull it open.
That said. I believe the answer is 1, and here's why. The notation x(y+z) is a very strong signal for the distributive property of parenthetical math notation such that it is logical to replace 2(1+2) with (2*1+2*2) => 6/(2*1+2*2) = 1. Furthermore, the commutative property of multiplication should be assumed such that 6/2(1+2) = 6/(1+2)2. Again implying that the answer must be 1.
That said. I believe the answer is 1, and here's why. The notation x(y+z) is a very strong signal for the distributive property of parenthetical math notation such that it is logical to replace 2(1+2) with (2*1+2*2) => 6/(2*1+2*2) = 1. Furthermore, the commutative property of multiplication should be assumed such that 6/2(1+2) = 6/(1+2)2. Again implying that the answer must be 1.