F(b-1) = (b-1)^2 + 2(b-1) + 1F(b-1) = b^2 - 2b + 1 + 2b - 2 + 1F(b-1) = b^2 - b
Therefore, F(b-1) = b^2 - b.
F(b-1) = (b-1)^2 + 2(b-1) + 1
F(b-1) = b^2 - 2b + 1 + 2b - 2 + 1
F(b-1) = b^2 - b
Therefore, F(b-1) = b^2 - b.