Factorize:

a2 + 2ab + b2 – 9c2

We have,



= (a + b)2 – 9c2


We can also write the expression as:


= [(a + b)2 – (3c)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:


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