How to do this maths question

Q.1)
Identity: x^2 + 2x +1 ≡ (x + 1)^2.
Equation: x - 8 = 11.
- Similarities: they both contain x. (I cannot think of any more.)
- Differences: An identity holds for all values of x, while equation holds only for a certain value of x.

Q.2)
L.H.S.
= A(x + 1)^2 - Bx^2
= A(x^2 + 2x + 1) - Bx^2
= Ax^2 + 2Ax + A - Bx^2
= (A - B)x^2 + (2A)x + (A)

R.H.S.
= (Cx + D)(D - Ex)
= CDx - CEx^2 + D^2 - DEx
= (-CE)x^2 + (CD - DE)x + (D^2)

For the identity to hold,
A - B = -CE---------------(1)
and 2A = CD - DE------(2)
and A = D^2.--------------(3)

For D = 1, A = 1. (by (3))
Sub. A = 1 into (2), 2 = C - E
C = 2 + E.
Sub. C = 2 + E into (1), 1 - B = -(2+E)(E)
1 - B = - E^2 - 2E
B = E^2 + 2E + 1
B = (E + 1)^2
For B = 4, E = 1.
∴ C = 3.
∴ When A = 1, B = 4, C = 3, D = 1 and E = 1, the identity holds.
(P.S. There should be other possible answers for A, B, C, D and E.)