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

1 Answer
May 7, 2016

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."