Question 914225

use the factor theorem  and factor {{{x^3 - x^2 - x - 15}}} to see if {{{x-3}}} is a factor 

{{{x^3 - x^2 - x - 15}}} ....write {{{-x^2}}} as {{{2x^2-3x^2}}} and {{{-x}}} as {{{5x-6x}}} 

{{{x^3+2x^2+5x-3x^2-6x-15}}} group


{{{(x^3-3x^2)+(2x^2-6x)+(5x-15)}}}

{{{x^2(x-3)+2x(x-3)+5(x-3)}}}


{{{(x-3)(x^2+2x+5)}}} ...so, {{{x-3}}} is a factor