Question

how do u determine the number of positive negative and complex zeros in f(x)=4x^3 -3x^2 +10x -5

Answer 1

@satellite73

Answer 2

hello again

Answer 3

hi im in a big hurry and have 2 problems to do

Answer 4

you want the zeros or the possible zeros?

Answer 5

the zeros im pretty sure

Answer 6

there is only one zero and it is positive but you cannot find it
i think they want you to use descartes rule of sign

Answer 7

there are 3 changes in sign of the coefficients, so there are either positive zeros and no complex zerso, or one positive zero and 2 complex zeros
in fact there is one positive and two complex

Answer 8

i am not sure what your answer choices are

Answer 9

also note that
\[f(-x)=-4x^3-3x^2-10x-5\] so there are NO possible negative zeros

Answer 10

there are no choices it just says demonstrate how to determine the number of positive negative and complex zeros

Answer 11

ok
say that
\[f(x)=4x^3 -3x^2 +10x -5
\] has three changes in sign, from \(+4\) to \(-3\), from \(-3\) to \(+10\) and from \(+10\) to \(-5\)
therefore there are either 3 positive zeros and no complex zeros (since there are at most thee zeros) or 1 positive zero and two complex zeros, since you count down by twos

Answer 12

then say
\[f(-x)=-4x^3-3x^2-10x-5\] has NO changes in sign, so there cannot be any negative zeros

Answer 13

conclusion
1 positive, two complex OR
3 positive no complex

in fact there is only one positive and two complex zeros, but i don't think it is asking you the actual answer, just the how to find the possible ones

Answer 14

thank you soo much

Answer 15

yw
on line class?

Answer 16

yes i have one more can you please help

Answer 17

k

Answer 18

write a polynomial function using the roots 1, -2 and 3i

Answer 19

how quick you want it?

Answer 20

pretty quick lol

Answer 21

i mean you want the method or the answer ?

Answer 22

awnser please

Answer 23

junt the funtion not solved

Answer 24

ok then we multiply
\[(x-1)(x+2)(x^2+9)\] using wolfram

Answer 25

and get \[x^4+x^3+7 x^2+9 x-18\]

Answer 26

http://www.wolframalpha.com/input/?i=%28x-1%29%28x%2B2%29%28x^2%2B9%29

Answer 27

so that would be the function?

Answer 28

\[f(x)=x^4+x^3+7 x^2+9 x-18\]

Answer 29

yes, that is it

Answer 30

thank u

Answer 31

yw

Answer 32

you done?

Answer 33

yes thank youu

Answer 34

whew
take a break from math
glad to help

Answer 35

wait sorry one more thing :)

Answer 36

what are the steps to solving tht

Answer 37

wait nvm got it