(b-6)(b*b +6b+36)-(b-2)(b+3) = b^3 + 6b^2 +36b - 6b^2 - 36b - 216 - (b^2 + b - 6) = b^3 + 6b^2 +36b - 6b^2 - 36b - 216 - b^2 - b + 6 = b^3 - b^2 - b - 210
(b-6)(b*b +6b+36)-(b-2)(b+3) = b^3 + 6b^2 +36b - 6b^2 - 36b - 216 - (b^2 + b - 6) = b^3 + 6b^2 +36b - 6b^2 - 36b - 216 - b^2 - b + 6 = b^3 - b^2 - b - 210