solve the equation x^3-5x^2-2x+24=0

gorila7

solve the equation x^3-5x^2-2x+24=0

help

Reply 1

problemsolver

-2 is a root

trial and error is worth a go if you're doing exam questions

Reply 2

fudgesundae

Original post by gorila7

solve the equation x^3-5x^2-2x+24=0

help

try the factor theorem. Essentially trial and error until you get your first factor. After that, give algebraic long division a go to get the other factors. Or just keep doing the factor theorem.

Reply 3

Woffles

If this is the only thing you're given then it would seem that factor theorem is the only way to go. Once you find one root, you can use division to find the remaining.

Reply 4

TobeTheHero

use the factor theorem :smile:

Reply 5

gorila7

Original post by Woffles

If this is the only thing you're given then it would seem that factor theorem is the only way to go. Once you find one root, you can use division to find the remaining.

Can you show me how to do this

Reply 6

gorila7

Original post by TobeTheHero

use the factor theorem :smile:

can you show me how to do this

Reply 7

gorila7

Original post by problemsolver

-2 is a root

trial and error is worth a go if you're doing exam questions

can you show me how to do this

Reply 8

TenOfThem

First you put some numbers in to see which one(s) will give 0

Can you see why -2 was given by the posters above

Reply 9

Rennit

If x=2 is a solution, then f(-2) = o since x-2=0 which makes the rest of the polynomial equal zero. Then write it as a quadratic of form ax^2+bx+c multiplied by a bracket and find the co-efficients of the quadratic. Then solve; you have your equation solved.