How do you determine the binomial factors of $x^3+x^2-4x-4$ ?

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Answer 1 · 2017-07-19T13:01:56

$=(x+1)(x+2)(x-2)$

Group the four terms into two pairs, making sure there is a + sign between them. Then take out a common factor from each.

$(x^3 +x^2) + (-4x-4)$

$=x^2(x+1)-4(x+1)" "larr$ note the change in signs!

There is a common bracket in the two terms:

$=(x+1)(x^2-4)" "larr$ factor the difference of squares

$=(x+1)(x+2)(x-2)$

How do you determine the binomial factors of x^3+x^2-4x-4x^3+x^2-4x-4?