Respuesta :

Answer:

A.  3x+2

Step-by-step explanation:

9x^2 + 12x + 4

can be factored:

(3x+2)(3x+2)

All sides of a square are the same length.  The area is two of the sides multiplied together.  Thus, (3x+2) must be the length of a side (all sides, actually)

3x+2