3(1-4b)^2-3(4b+1)(1-4b)
3(1 - 8b + 16b^2) - 3(1 - 16b^2) = = 3 - 24b + 48b^2 - 3 + 48b^2 = = 96b^2 - 24b = = 24b (4b - 1)