Which of the following is a polynomial with roots -2, -3i, and 3i ?

Question

campbell_st · Answer

well with roots of 3i, -3i and -2you can have a polynomial 

P(x) = (x -3i)(x + 3i)(x + 2) 

just distribute and the first 2 binomial factors will be the difference of 2 squares

anonymous · Answer

-3i?

campbell_st · Answer

its a complex number solution....

what you need to know is 

$$i^2 = -1$$

so 

$$3i \times -3i = -9i^2$$

now subsitute $$i^2 = -1 $$

and its

$$-9 \times -1 = 9$$

anonymous · Answer

x3 + 4x2 + 9x + 24
	x3 - 4x2 + 9x - 24
	x3 + 2x2 + 9x + 18
	x3 - 2x2 + 9x - 18

campbell_st · Answer

well not quite if you start with the 1st 2 binomials 

P(x) = (x - 3i)(x + 3i)(x + 2)

(x - 3i)(x + 3i) = x^2 -3xi + 3xi -9i^2 

which I've simplified below

$$P(x) = (x^2 + 9)(x + 2)$$

campbell_st · Answer

you just need to distribute to get your polynomial

anonymous · Answer

oh ok