# What are the excluded values and how do you simplify the rational expression (2r-12)/(r^2-36)?

$\frac{2 \left(r - 6\right)}{\left(r - 6\right) \left(r + 6\right)}$
$\frac{2}{r + 6}$
We cannot have $r = \pm 6$ because it would make the expression undefined.