Question 238391
{{{(r^2-4)/(3r+6)=((r+2)(r-2))/(3*(r+2))}}}
{{{(r^2-4)/(3r+6)=(cross((r+2))(r-2))/(3*cross((r+2)))}}}
{{{(r^2-4)/(3r+6)=(r-2)/3}}}