Question

Find all the zeroes of the equation. –3x4+ 27x2 + 1200 = 0

Answer 1

-3(x^4 - 9x^2 - 400) = 0

Answer 2

So it is because the GCF is -3??

Answer 3

yea....

Answer 4

I know the real roots are -5 and 5. Don't I need that to find out??

Answer 5

so they already gave you these roots? u shouldve put put them along with the question

Answer 6

use synthetic division then!

Answer 7

use that synthetic division to find the other roots

Answer 8

No, I figured out the roots with a graphing calculator and my answers were off after doing synthetic division.

Answer 9

ok!!

Answer 10

Alright. I'll just re-do the problem and thanks for the help( :

Answer 11

om wait! lets work it out tpgether!

Answer 12

Alright.

Answer 13

do you know how to find rational zeros?

Answer 14

So I need to figure out the zeros of the equation –3x4+ 27x2 + 1200 = 0. In my book it tells me that I need to find the real roots which are -5 and 5 and then use the synthetic division.

Answer 15

I'm sure I would if I saw how to but not really.

Answer 16

oh ok!
-3(x^4 - 9x^2 - 400) = 0
-3(x^2 - 25)(x^2 + 16) = 0

Answer 17

Set each factor equal to zero

Answer 18

x^2 - 25 = 0
x = 5, -5

Answer 19

Ohh! This is where I get confused...what do I need to do with -3?

Answer 20

x^2 + 16 = 0
x = 4i, -4i

Answer 21

Just leave that out!!!

Answer 22

Because when you set =3 equal to zero: -3 = 0
they are NOT equal to zero!!!!!

Answer 23

But when you simplify, you should write it out as:
-3(x^2 + 16)(x-5)(x+5) = 0

Answer 24

Nope! They aren't equal to 0. And I get it now!! Thanks for your help( :

Answer 25

Its ok!! Thank you for the medal!!!!!!! :)

Answer 26

No problem( :

Answer 27

:)