Question 107656
{{{r^2/(r-s) + s^2/(s-r)=r^2/(r-s) + s^2/(-(r-s))}}}Get the same denominator, (r-s).
{{{r^2/(r-s) + s^2/(s-r)=r^2/(r-s) + (-s^2)/(r-s)}}}
{{{r^2/(r-s) + s^2/(s-r)=(r^2-s^2)/(r-s)}}}Subtract numerators.

{{{r^2/(r-s) + s^2/(s-r)=((r+s)cross(r-s))/cross(r-s)}}}Factor the quadratic.
{{{r^2/(r-s) + s^2/(s-r)=r+s}}}