# How do you factor a² + 2ab + b² - x² - 6x - 9?

$\left(a + b + x + 3\right) \left(a + b - x - 3\right)$.
Use ${A}^{2} - {B}^{3} = \left(A + B\right) \left(A - B\right)$
The expression is ${\left(a + b\right)}^{2} - {\left(x + 3\right)}^{2}$
$\left(a + b + x + 3\right) \left(a + b - x - 3\right)$.