What is the difference of the following polynomials?

6x^3 – 2x^2 + 4
–(2x^3 + 4x – 5)

To find the difference of the two polynomials, we need to distribute the negative sign in front of the second polynomial.

So, 6x^3 - 2x^2 + 4 - (2x^3 + 4x - 5) becomes:
6x^3 - 2x^2 + 4 - 2x^3 - 4x + 5

Combine like terms:
(6x^3 - 2x^3) - 2x^2 - 4x + 4 + 5
4x^3 - 2x^2 - 4x + 9

So, the difference of the two polynomials is 4x^3 - 2x^2 - 4x + 9.