Respuesta :

Answer:

(fg)(x) = 12x^3 + 9x^2 + 28x + 21

Third option

Step-by-step explanation:

(fg)(x) = (3x^2 + 7)(4x + 3)

(fg)(x) = = (3x^2)(4x) + (3x^2)(3) + (7)(4x) + (7)(3)

(fg)(x) = 12x^3 + 9x^2 + 28x + 21