Question

Which of the following is a polynomial with roots 3, -3i, and 3i ?

x3 + 3x2 + 9x + 27
x3 - 3x2 + 9x - 27
x3 + 9x2 + 9x + 81
x3 - 9x2 + 9x - 81
The little "i" thingies confuse me. :c

Answer 1

i=sqrt(-1)
i^2 =-1
i^3=(i)(i^2)=-i
polynomial with 3, -3i, 3i is
(x-3)(x+3i)(x-3i)
=(x^2+3ix-3x-9i)(x-3i)
=x^3-3ix^2+3ix^2+9x-3x^2+9ix-9ix-27
=x^3-3x^2+9x-27

Answer 2

Thank you sooo much :3 You're fantastic.

Answer 3

You are welcome