How do you factor $x^3-81x$ ?

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Answer 1 · 2016-05-30T21:08:07

$x(x + 9)(x - 9)$

Take out a common factor of $x$ first.
$x(x^2 - 81)$
This gives the difference between two squares, so we can factorise again...

$x(x + 9)(x - 9)$

How do you factor x^3-81xx^3-81x?