How do you factor 4x^2 + 4xy +y^2?

Jun 13, 2015

$4 {x}^{2} + 4 x y + {y}^{2} = {\left(2 x + y\right)}^{2}$

Explanation:

This is a perfect square trinomial and especially easy to spot if you know your square numbers: $441 = {21}^{2}$