Add.

(2x^2 + 4 - x^3) + (-4x^2 + 6x^3 - 2)

5x^3 - 2x^2 + 2

Step-by-step explanation:

First, distribute the addition sign to get rid of the parentheses

2x^2 + 4 - x^3 - 4x^2 + 6x^3 - 2

then combine like terms

-2x^2 + 2 + 5x^3

then order them in deacreaing power of x

5x^3 - 2x^2 + 2