# How do you factor completely: x^2 +4x +4?

We know: ${\left(x + y\right)}^{2} = {x}^{2} + 2 x y + {y}^{2}$ (Memorise)
Thus, we have: ${x}^{2} + 4 x + 4 = {x}^{2} + 2 \left(2\right) x + {2}^{2} = {\left(x + 2\right)}^{2}$