Question 1149306
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My rule is:


<pre>
    If I can not guess factoring in 5 seconds, I use the quadratic formula to find the roots 
    of the associated quadratic equation {{{x[1]}}} and {{{x[2]}}} 


    As soon as I know the roots, the factoring form is  {{{a*(x-x[1])*(x-x[2])}}},

    where coefficient "a" is the leading coefficient at x^2 in the original polynomial.



    Doing this way, I save my brain from unnecessary job.
</pre>