Question

I GIVE MEDALS

Find all the zeros of each polynomial function.

f(x) = x4 – 5x2 – 36

a. ±3, ±2i
b. ±3 only
c. ±2i only
d. none of the above

Answer 1

@dhirensharma

Answer 2

Hint :-
let y = x^2
then solve the quadratic for y

Answer 3

it is y=x^2

Answer 4

zeros = 9,-9,-2

Answer 5

@ninaesb ??

Answer 6

im sorry , that was wrong . it was from a different problem .

Answer 7

y^2 - 5y - 36 = 0
(y - 9)(y + 5) = 0

so solution set for y is {-5 ,9}

so we have x^2 = 9 or x^2 = -5

Answer 8

@cwrw238 was there a typo?

Answer 9

ooops s sorry
its (x - 9)(x + 4) = 0

yea

y = 9 or -4

Answer 10

so x = +/- sqrt 9 , +/- sqrt(-4)

Answer 11

none of the above

Answer 12

i just got back

Answer 13

u sure?

whats sqrt 9?

Answer 14

oh 3

Answer 15

+/- 3

Answer 16

and 2

Answer 17

what about +/- sqrt (-4)
have you came across the value i ?

Answer 18

i = sqrt(-1)

Answer 19

it is not real but an imaginary number

Answer 20

so i^2 = -1

and 2i * 2i = 4i^2 = -4
and
-2i * -2i = 4i^2 = -4

Answer 21

and the square of that is 2

Answer 22

the square of what is 2?

Answer 23

of 4
right?

Answer 24

so it would be a

Answer 25

no the square of 2i is -4
and also th square of -2i is -4

so the square roots of -4 are 2i and -2i

Answer 26

so which option is the correct answer?

Answer 27

oh so c

Answer 28

dont forget the other 2 zeros....

Answer 29

\((2i)^2=(2^2 i^2)=4(-1)=-4\)
\((-2i)^2=((-2)^2 i^2)=4(-1)=-4\)

Answer 30

ok if its 4 then its none of the above

Answer 31

patience is a virtue...

Answer 32

its a chantz417

Answer 33

i said that along time ago!!!

Answer 34

so you did...

Answer 35

you told me no

Answer 36

the zeros are +/- 3 and +/- 2i

Answer 37

!!!!!!!!!!!!!!!!!!!!!!

Answer 38

sorry - i got confused when you talked about the square of 2 and of 4