Given polynomial f(x)=x^3-2x^2-40x-64f(x)=x32x240x64 and a factor x-8x8 how do you find all other factors?

1 Answer
Feb 23, 2017

The other factors are (x+2)(x+2) and (x+4)(x+4)

Explanation:

We perform a synthetic division

color(white)(aaaa)aaaa88color(white)(aaaa)aaaa|color(white)(aaaa)aaaa11color(white)(aaaa)aaaa-22color(white)(aaaaa)aaaaa-4040color(white)(aaaaaa)aaaaaa-6464

color(white)(aaaaaa)aaaaaacolor(white)(aaaa)aaaa|color(white)(aaa)aaacolor(white)(aaaaaaa)aaaaaaa88color(white)(aaaaaa)aaaaaa4848color(white)(aaaaaaaa)aaaaaaaa6464

color(white)(aaaaaaaaaa)aaaaaaaaaa------------------------------------------------------------

color(white)(aaaa)aaaacolor(white)(aaaaaa)aaaaaacolor(white)(aaaaaa)aaaaaa11color(white)(aaaaa)aaaaa66color(white)(aaaaaaa)aaaaaaa88color(white)(aaaaaaaa)aaaaaaaacolor(red)(0)0

The remainder is =0=0

The quotient is =x^2+6x+8=x2+6x+8

This is factorised as

x^2+6x+8=(x+2)(x+4)x2+6x+8=(x+2)(x+4)