Find all real zeros of the function algebraically.

f(x)= x^4 - x^3 - 15x^2

help anyone?

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- May 1st 2013, 09:37 AMcaptaincrunch383Find all the zeros of the function algebraically.
Find all real zeros of the function algebraically.

f(x)= x^4 - x^3 - 15x^2

help anyone? - May 1st 2013, 10:20 AMShakarriRe: Find all the zeros of the function algebraically.
$\displaystyle x^4-x^3-15x^2=x^2(x^2-x-15)$

Can you find all the zeros in that? - May 1st 2013, 10:35 AMcaptaincrunch383Re: Find all the zeros of the function algebraically.
- May 1st 2013, 10:40 AMsciencepalRe: Find all the zeros of the function algebraically.
0,0,$\displaystyle 1\pm\sqrt{61}/2$

- May 1st 2013, 10:41 AMcaptaincrunch383Re: Find all the zeros of the function algebraically.
- May 1st 2013, 10:42 AMdokrbbRe: Find all the zeros of the function algebraically.
Shakarri meant that one, $\displaystyle x^2(x^2-x-15)$

now you have in the brackets a second degree equation, it's impossible that you can not find the zeros from that one, try it,

ps: oops, we might have answered in the same time - May 1st 2013, 10:42 AMcaptaincrunch383Re: Find all the zeros of the function algebraically.
- May 1st 2013, 10:52 AMShakarriRe: Find all the zeros of the function algebraically.
$\displaystyle x^2(x^2-x-15)$ is zero when either $\displaystyle x^2=0$ or $\displaystyle x^2-x-15=0$

Find the values of x which make either of those zero. - May 1st 2013, 10:58 AMcaptaincrunch383Re: Find all the zeros of the function algebraically.
- May 1st 2013, 11:23 AMcaptaincrunch383Re: Find all the zeros of the function algebraically.
Never mind i got it.