Respuesta :

2x^4 + 3x^2 + 7 + 3x^4 - 9x^2 - 4x + 4
= 5x^4 - 6x^2 - 4x  + 11

answer is C. 5x^4 - 6x^2 - 4x  + 11
The answer is 5x^4-6x^2-4x+11, or in your case, C