The first time I tried this problem I found it challenging because I was trying to add the coefficients of the radicals without factoring the the radicands first. I went over this question with my tutor and I looked at the answer key and tried to work backwards, I was still a little bit confused so as I was working through the question I would go back and forth and look at the notes while I was solving the question. I kept doing this until I got the question correct. In the future when I encounter a difficult concept like this I will do some workbook questions with the notes and some questions without.