Problem: 6cosx+2=-1

Directions: solve for x. a)Write an expression that identifies all possible real answers (n= any integer) b) Give an answer that is within the principal values.

We went over this today in class, the answers were: a) 120+360n and 240+360n b) x=120

I'm confused about how to arrive at this answer. Also, is it possible to solve this without a graphing calculator?