You are trying to figure out I think what x equals. So you can set it up in 2 different ways. One is since you know the answer and what it equals and a the number times whatever, you can set it up as 30 divided by 6= x, since you don't know what x is.
Or you can set it up like how it already is, and do 6 times x= 30.
All in all, the answer is 5!
Hope this helps, have a good day. c;