Answer
$(r+s)(r-s)$
Work Step by Step
We are given the denominators $r+s$, $r-s$, and $r^{2}-s^{2}$.
In order to find the least common denominator, we must factor each denominator.
$r+s$ cannot be simplified further
$r-s$ cannot be simplified further
$r^{2}-s^{2}=(r+s)(r-s)$
Next, we multiply together all distinct factors from each denominator, with each factor raised to the greatest power that occurs in any denominator.
$LCD=(r+s)(r-s)$
