I just finished this paper
![Smiley :)](https://studentforums.biz/Smileys/default/smiley.gif)
So basically try to think of all possible combinations that would give terms with
![x^2](https://studentforums.biz/cgi-bin/mimetex.cgi?x^2)
From the first part that you calculated
if you multiply this term with
![(1+2x+ax^2)](https://studentforums.biz/cgi-bin/mimetex.cgi?(1+2x+ax^2))
possible terms with
![x^2](https://studentforums.biz/cgi-bin/mimetex.cgi?x^2)
would be
![64X ax^2](https://studentforums.biz/cgi-bin/mimetex.cgi?64X ax^2)
,
![-192x X 2x](https://studentforums.biz/cgi-bin/mimetex.cgi?-192x X 2x)
, &
![240x^2 X 1](https://studentforums.biz/cgi-bin/mimetex.cgi?240x^2 X 1)
The sum of their co-efficient = 48 given in the question
64a- (192X2) + 240=48
64a= 48-240+(192X2)
64a= 192
a=192/64
![a=3](https://studentforums.biz/cgi-bin/mimetex.cgi?a=3)