Respuesta :

3x^3 - 4x^2 + 6x - (5x^3 + 2x^2 - 3x) = 
3x^3 - 4x^2 + 6x - 5x^3 - 2x^2 + 3x = 
-2x^3 - 6x^2 + 9x <====
A is the answer to your question