# How to factorize an equation?

How can I quickly factorize an equation without using Ruffini's rule or polynomial division?

Take this equation as an example:

x^4-9x^2+20x=0

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## migrated from mathematica.stackexchange.comOct 28 '13 at 19:08

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possible duplicate of Factoring polynomials to factors involving complex coefficients –  Artes Oct 28 '13 at 18:21
Make the substitution $x^2=\eta$, then you have a quadratic. –  Hakim Apr 1 at 21:19