Question 174806
 how do i multiply r^2+7r+10/3 by 3r-30/r^2-5r-50?
---------------
The same as any other fractions.  You multiply the NUMs and the DENs.
{{{((r^2+7r+10)/3)*((3r-30)/(r^2-5r-50))}}}
={{{((r^2+7r+10)*(3r-30))/(3*(r^2-5r-50))}}}
Cancel the 3s
={{{((r^2+7r+10)*(3r-30))/(3*(r^2-5r-50))}}}
={{{((r+5)*(r+2)*(r-10))/((r-10)*(r+5))}}}
Cancel (r+5) and (r-10)
={{{(r+2)}}}