Quotient ring, cosets

[Schril]

Hey guys, first time here I've been stuck on where to start for this question, I have got how the cosets would be in the form 'a+bx+I' for where 'I=(x^2+3)' and 'a,b∈ Q', though am not sure where to go from here, any help would be appreciated:

 

[Steven G]

You have to know showing about this problem.
Have you worked out any of these type problems yet?
Is there an example you have the solution for that you do not understand? If yes, then please post it, tell us what you do not understand and we will walk you through the steps. After you do a few of these type problems they become routine. The thing is that you have to work a few. Please post back.