# How do you write a polynomial function of least degree given the zeros -1, 2i?

##### 1 Answer

Nov 15, 2016

Please see the explanation

#### Explanation:

The zero at -1 implies that (x + 1) is a factor:

The zero at 2i implies that (x - 2i) is a factor.

The zero at 2i implies that -2i is, also, a zero and, therefore, (x + 2i) is a factor.

We know that the product of complex conjugates

Use the F.O.I.L method to multiply:

Rearrange in descending power: