How do you factor completely # x^3 + px^2 - x - 2#?

1 Answer
May 7, 2016

Answer:

There are 4 terms - group them in pairs.
=#(x + 2)(x^2 - 1)# if #p=2#

Explanation:

#x^3 + px^2 - x - 2# = #(x^3 + px^2) + ( - x - 2)#

= #x^2(x + p) - (x + 2) " "# This will only factor if p = 2

=#(x + 2)(x^2 - 1)#

I suspect that the question should have read something like,
"find the value of p by factorising."