1. The problem statement, all variables and given/known data order 3 radical from (9+4radical5) + order 3 radical from (9-4radical5) *note: 9+4radical5 is all under the big order 3 radical. (so is the other one) 2. Relevant equations in case you don't understand what i wrote (sorry, my language is not english and math linguistics differ in my language) click the attachement to see a picture of the equation 3. The attempt at a solution I think i might find the solution by writing 9+4radical5 as a cube of something so as to cancel the radical but what if i have order 6 radical? (because i have this type of exercises as the next one. So clearly writing as a square, cube etc won't work everytime. Thank you!