I'm going to do this the long way, finding everything, but there are shorter methods if all you are trying to do is order n^2. I'm also going to start by removing the brackets in each question.
A
- 5n^3 + 5n^2 + 5 + n^3 - n^2
-4n^3 + 4n^2 + 5
B
n^3 + 2n^2 - n - 2 - (n^3 - 3n^2)
n^3 + 3n^2 - n - 3 - n^3 + 3n^2
5n^2 - n - 2
C
n^2(n - 4)+ 5n^3 - 6
n^3 - 4n^2 + 5n^3 - 6
6n^3 - 4n^2 - 6
D
2n^3 - 4n^2 - 2n + 3n^2
2n^3 - n^2 - 2n
The correct order is bad C or B A D C.
I don't know what to put into the boxes. You might have to ask about that.
The numbers in front of the coefficients for x^2 are
B = 5
A = 4
D = - 1
C = - 4