Alyssamonettid
Answered

PLEASE HELP
The polynomial function f(x) = -x^3 –x^2 + 4x +9 has one positive zero.
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Between what integers does this positive zero occur?

Sagot :

Answer:

(x + 2) ( x - 3) (x - 4)  =

 

(x^2 - x - 6)  ( x - 4)  =

 

x^3  - x^2  - 6x

       -4x^2 + 4x  + 24

_________________

x^3  - 5x^2 - 2x + 24

 

So  we have

 

1x^3  -5x^2 - 2x + 24

 

Second one

 

I'm assuming that this is  :

 

4x^7  -2x^4  + 2x^3 -4x - 9

 

We have  3  sign changes.....so the number of possible positive roots  =  3 or 1

 

To find the number of possible negative roots, replaxe x  with -x  and we have

 

4(-x)^7 - 2(-x)^4 + 2(-x)^3 -4(-x) - 9  =

 We have 2 sign changes....so the number of possible negative roots  = 2  or 0

-4x^7 -2x^4 - 2x^3 + 4x - 9     

 

Blackjacksevenid

 

Answer:

(x + 2) ( x - 3) (x - 4)  =

 (x^2 - x - 6)  ( x - 4)  =

  x^3  - x^2  - 6x

 -4x^2 + 4x  + 2

_________________

x^3  - 5x^2 - 2x + 24

So  we have

 1x^3  -5x^2 - 2x + 24

 Second one

I'm assuming that this is  :

4x^7  -2x^4  + 2x^3 -4x - 9

 We have  3  sign changes.....so the number of possible positive roots  =  3 or 1

 To find the number of possible negative roots, replaxe x  with -x  and we have

4(-x)^7 - 2(-x)^4 + 2(-x)^3 -4(-x) - 9  =

 We have 2 sign changes....so the number of possible negative roots  = 2  or 0

-4x^7 -2x^4 - 2x^3 + 4x - 9