What is the third–degree polynomial function such that f(0) = –18 and whose zeros are 1, 2, and 3

Answer 1

The zeroes are 1, 2, and 3, so the factors are (x-1), (x-2), and (x-3). Those are 3 factors for a 3rd degree polynomial, so no other factors are needed.

f(x) = C*(x-1)(x-2)(x-3), where C is any constant.

f(0) = 18 allows you to determine C.