# How do you factor x^2 + 6x + 9 - y^2?

$\left[\left({x}^{2} + 6 x + 9\right) - {y}^{2}\right] = {\left(x + 3\right)}^{2} - {y}^{2} = \left(x + 3 - y\right) \left(x + 3 + y\right)$