It's nine.
The reason it is nine is because of PEMDAS. If you did not know, PEMDAS stands for Parentheses, Exponents, Multiplication and Division, and finally, Addition and Subtraction. The reason M is grouped up with D is because they are inverse operations, just like A and S; they undo each other.
So, let's apply this to the problem.
6/2(2+1) - Perform the action inside the parentheses, which would be 2+1, which gives us 3.
6/2*3 - Divide 6 and 2 to get 3.
3*3 - Three times three, or 3^2, is 9.
Distributive property would necessarily only apply to an equation where you would find a variable of some kind, such as 4(2+x)=8.
Oh, and spoiler, the answer to that equation would be x=0.
