Respuesta :

Answer:

  D.  2x^2

Step-by-step explanation:

Considering only the x^2 terms, you have ...

  -4x^2 -? = -6x^2

Add 6x^2 to get ...

  2x^2 -? = 0

Add "?" and you have ...

  2x^2 = ? . . . . . . matches choice D