How do you factor $x^3-4x^2-36x+144$ by grouping?

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Answer 1 · 2016-08-07T11:41:33

$x^3-4x^2-36x+144 = (x+6)(x-6)(x-4)$

$x^3-4x^2-36x+144$

= $x^2(x-4)-36(x-4)$

= $(x^2-36)(x-4)$

= $(x^2-6x+6x-36)(x-4)$

= $(x(x-6)+6(x-6))(x-4)$

= $(x+6) (x-6) (x-4)$

How do you factor x^3-4x^2-36x+144x^3-4x^2-36x+144 by grouping?