Factorise:
9x2+6xy+y2
Given 9x2+6xy+y2
Express the middle term 6xy as sum of two terms such that their product is equals the product of extreme terms(9x2y2).
So, 6xy=3xy+3xy and also 3xy×3xy=9x2y2
Thus, the given expression can be written as
=9x2+3xy+3xy+y2
=3x(3x+y)+y(3x+y)
=(3x+y)(3x+y)
=(3x+y)2
Therefore, the factorised form is (3x+y)2.