6-1/3x=-1 How do I do this

Im gonna assume you mean 6 - (1/3) x = - 1. Your notation is not super clear. If so, solution is as follows:

6 - (1/3) x = - 1 [subtract 6 from both sides]

- (1/3) x = - 7 [multiply both sides by - 3]

x = 21