Question

How do you write a polynomial in standard form given the zeros 5 and 1+2i?

Answer 1

`x^3-7x^2+15x-25`

Explanation:

If `1+2i` is root of a polynomial, `1-2i` also the root of it. Hence,

`P(x)=(x-5)(x-1+2i)(x-1-2i)`

=`(x-5)(x^2-2x+5)`

=`x^3-7x^2+15x-25`