Use Solve result as a function of parameters

Like the attached screenshot, I am trying to find b2 maximising a function I named ‘EG1EUB’.
And ‘EG1EUBb2’ is the frist order condition.
Based on my understanding, Solve gave me a single solution saying that b2 is the second root.
And I believe that ‘#’ is indicating b2.
So I want to take this second root as a new function of thetab1 and thetab2 which are parameters of my objective function. However, I couldn’t find out how to do that. Below is my notebook that I am working on.

I found out that I cannot delet this.
Someone else provided me solution.
Just in case I’m leaving the link to that page
https://mathematica.stackexchange.com/q/280697/90555