Respuesta :

(3(4a^2 - 1)/2) x (2x + 1)^-2 x (2x +1)/6
(4x^2 -1)/2 x (2x+1)^-2 x (2x + 1)/2
((4x^2-1) x (2x+1)^-2 x (2x+1))/4
((2x-1) x (2x+1))/4(2x+1)

Answer: (2x-1)/4