Watch these videos. Factoring a trinomial requires two steps. First, a common monomial factor is factored out, and then the resulting polynomial is factored by grouping. The second video gives an example of a multi-step factoring process by factoring out a common monomial and then using the difference of cubes formula.
Source: Khan Academy, https://youtu.be/d-2Lcp0QKfI, https://youtu.be/CxcP4ylUP5w
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