# How do you simplify (x + 3)/(x^2 + 5x + 6)?

${x}^{2} + 5 x + 6 = \left(x + 2\right) \left(x + 3\right)$
$\frac{x + 3}{{x}^{2} + 5 x + 6} = \frac{\cancel{x + 3}}{\left(x + 2\right) \cancel{\left(x + 3\right)}} = \frac{1}{x + 2}$
...provided $x \ne - 3$ (and $x \ne - 2$)