Question

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

Answer 1

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."