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N^2 - n - 20 factor completely I have trouble doing this in math

User Dguan
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1 Answer

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To factorize this expression, we start by "looking" for two terms whose sum will give "-n" and whose product will give "-20n-squared"


\begin{gathered} n^2\text{ - n - 20} \\ \text{This terms are (-5n and +4n)} \\ \text{Next, we replace the middle term (-n) with these new terms } \\ n^2\text{ -5n + 4n - 20} \\ n(n\text{ - 5) + 4(n - 5)} \\ (n\text{ + 4)(n - 5)} \end{gathered}

User Tibidabo
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