What is a ^ 2 + A + 1-A ^ 3 (A-1)?

What is a ^ 2 + A + 1-A ^ 3 (A-1)?

Original formula = [(A-1) (a ^ 2 + A + 1) - A ^ 3] \ (A-1)
=(a^3-1-a^3)\(a-1)
=-1\(a-1)