Question

What is the difference for this question?

Answer 1

Removing the parentheses gives
5x^2 + 2x + 11 - 7 - 4x  + 2x^2
= 7x^2 - 2x + 4

Answer 2

For this case we have the following polynomials:
 (5x2 + 2x + 11) - (7 + 4x - 2x2)
 Rewriting we have:
 5x2 + 2x + 11 - 7 - 4x + 2x2
 By grouping terms of the same degree we have:
 x2 (5 + 2) + x (2-4) + (11-7)
 Rewriting:
 7x2 - 2x + 4
 Answer: the difference is
 7x2 - 2x + 4