Write a function in standard form that has the zeros 3 and i

Answer 1

Since i is a root, so is -i (assuming that the polynomial has real coefficients).

f(x) = (x - 3)(x - i)(x - (-i))

= (x - 3)(x - i)(x + i)

= (x - 3)(x² + 1) = x³ - 3x² + x - 3