How do you factor $x^3-3x^2-4x+12$ ?

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Answer 1 · 2017-05-03T10:33:30

$=(x-3)(x+2)(x-2)$

$x^3 -3x^2 -4x +12" "larr$ group into pairs

$=(x^3 -3x^2)+ (-4x +12)" "larr$ there must be a $+$ between.

$x=^2(x-3)color(blue)(-4(x-3))" "larr div color(blue)(-4)$ out as the factor to change the signs.

$=(x-3)(x^2-4)" "larr$ factors further as difference of squares.

$=(x-3)(x+2)(x-2)$

How do you factor x^3-3x^2-4x+12x^3-3x^2-4x+12?