6÷2(1+2)

is the same as:

6/2*(1+2)

Putting something outside parentheses generally means that it is multiplied by whatever is inside the parentheses. The exception to this would be a function call, such as for example: triple(1+2), which would return 9. Clearly "2" isn't a function, so 2(1+2) means 2*(1+2). / is the same as ÷, but easier to type.

Then the equation is simple, just follow the normal rules of operator precedence:

6/2*(1+2)
= 6/2*(3)
= 3 * 3
= 9