Question

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

x^3 + 2x^2 + 4x + 8
x^3 + 4x^2 + 4x + 16
x^3 - 4x^2 + 4x - 16
x^3 - 2x^2 + 4x - 8

Answer 1

Try substituting in the values for each polynomial, and see which one outputs zero

Answer 2

Oops, the values were
-2, -2i, and 2i

Answer 3

if -2 is a zero (x+2) is a factor
(x+2)(x+2i)(x-2i)

Answer 4

Well the constant coeiffient must be the -product of all 3 roots

Answer 5

its #1

Answer 6

-2*-2i*2i=4i*2i=-8, the additive inverse of -8, is 8, the only polynomial with 8 as a constatnt coeiffient is #1, so it must be that 1

Answer 7

The first one.

Answer 8

You're right, thank you. :)