Simplify the expression: ab^2 + 3a^3b - 8ab^2 + 4a^3b^2 + 2a^3b
ab^2 + 3a^3b - 8ab^2 + 4a^3b^2 + 2a^3b =
ab ( b + 3a^2 - 8b + 4ab + 2a^2 ) =
ab ( -7b + 5a^2 + 4ab)