Factorize:

m2 + 17mn – 84

We have,



Now by using middle-term splitting, we get


= m2 + 21mn– 4mn – 84n2


= m (m + 21n) – 4n (m + 21n)


= (m + 21n) (m – 4n)


Hence,


The given expression can be factorized as:



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