hi everyone,

I have this equation which has sigma notation. I need to expand the sigma into factors and solve for x.

my question is did I get the symmetry expansion right? I want to make sure before I try to solve for x. also, in general how do you think about this? I think you have 3 possible combinations in first factor. each of those has 3 combinations of a,b,c. 3+3+3=9 terms in total.

is this the total expansion?