# how can i solve this ??

• Sep 6th 2010, 07:59 AM
mido22
how can i solve this ??
i want the way to solve this equation without using calculator to find value of x
x3 + ax2 + bx + c
• Sep 6th 2010, 08:03 AM
yeKciM
Quote:

Originally Posted by mido22
i want the way to solve this equation without using calculator to find value of x
x3 + ax2 + bx + c

hm... check what did you wrote there ... :D (first are those x2 x3 $x_2 , x_3$ or are they just $3x, 2x$ , and where is there equation :D:D:D )
• Sep 6th 2010, 08:05 AM
mido22
Quote:

Originally Posted by yeKciM
hm... check what did you wrote there ... :D (first are those x2 x3 $x_2 , x_3$ or are they just $3x, 2x$ , and where is there equation :D:D:D )

they are x^3 + (a*x^2) + (b*x) + c =0
• Sep 6th 2010, 08:24 AM
yeKciM
Quote:

Originally Posted by mido22
they are x^3 + (a*x^2) + (b*x) + c =0

$x^3+ax^2+bx+c =0$

if you looking for formula to solve that in that form than.... hm... it's huge :D:D:D:D if those i assume constants a,b,c were numbers than could be shown how to reduce that equation so it could be solved easier :D

or you can use Horner scheme , but anyway you need one zero first :D
• Sep 6th 2010, 09:38 AM
mido22
Quote:

Originally Posted by yeKciM
$x^3+ax^2+bx+c =0$

if you looking for formula to solve that in that form than.... hm... it's huge :D:D:D:D if those i assume constants a,b,c were numbers than could be shown how to reduce that equation so it could be solved easier :D

or you can use Horner scheme , but anyway you need one zero first :D

here is the problem link :
https://www.spoj.pl/problems/ROOTCIPH/

what is your idea
• Sep 6th 2010, 02:36 PM
yeKciM
Quote:

Originally Posted by mido22
here is the problem link :
https://www.spoj.pl/problems/ROOTCIPH/

what is your idea

hm.....

try this if helps you : x&#94;3&#43;ax&#94;2&#43;bx&#43;c&#61;0 - Wolfram|Alpha

and here you are how to do cubic polynomial : Solving Cubic Equations

hm.... or because your are writing code for that, maybe it would be easier to test first zero, and than simplify cubic polynomial... as i recall you can use algorithm hm... can't remember right now but as soon as i do i'll write it here :D (long time passed since i have done any programming :D:D:D)
• Sep 6th 2010, 04:21 PM
mido22
Quote:

Originally Posted by yeKciM
hm.....

try this if helps you : x&#94;3&#43;ax&#94;2&#43;bx&#43;c&#61;0 - Wolfram|Alpha

and here you are how to do cubic polynomial : Solving Cubic Equations

hm.... or because your are writing code for that, maybe it would be easier to test first zero, and than simplify cubic polynomial... as i recall you can use algorithm hm... can't remember right now but as soon as i do i'll write it here :D (long time passed since i have done any programming :D:D:D)

ok take your time but don't forget me :D