Respuesta :

-3x^4 + 9x^3 -4x + 4 - 5x^4 - 9x + 2
= -8x^4 +9x^3 - 13x + 6

answer is A. -8x^4 +9x^3 - 13x + 6
A.  -8x^4+9x^3-13x+6

You have to distribute the negative in front of the second set of parentheses and then combine like terms :)