Question

Which of the following is a polynomial with roots -4, -2i, and 2i ?

Answer 1

if a polynomial with root a and b...then you can write it as (x-a)(x-b) = 0 , base on this, can you write your polynomial ?

Answer 2

i don't really understand

Answer 3

example , x - 3 = 0, what is the root here ? ..i.e what is the value of x ?

Answer 4

3

Answer 5

ok, so for example ...a polynomial of root 3 and 8 ...can you write this polonomial ?

Answer 6

x-3=0; x-8=0?

Answer 7

that is not a polynomail ...should write it as (x-3).(x-8) = 0 ...this mean either x = 3 or x = 8 ..will make this polynomal equal to zero , now base on this, write your polynomial

Answer 8

(x+4)(x+2i)(x-2i)=0?

Answer 9

ok, now do you know what i is? i.e ...definition of i

Answer 10

equals -1 or something like that

Answer 11

no..i = sqrt(-1) , ie...i^2 = -1 ...also use this formula ...(x+a).(x-a) = x^2 - a^2 ...can you simply your polynomial there?

Answer 12

no this confusing.

Answer 13

use this formula (x+a)(x-a) = x^2 - a^2 , tell me what is (x+2i).(x-2i) = ?

Answer 14

required poly..
is (x+4)(x^2+4)=X^3+4x^2+4x +16

Answer 15

@matricked, giving the answer is not the way of helping him understand at all

Answer 16

@tamtoan yup u r correct
but if the person is cofusing then c

Answer 17

:) see his new question ? ,, it's basically the samething..give answer, he won't be able to do other exact same problem

Answer 18

well i don't caree, and actually im a girl thank you :)