1. Factor r^2+7r=10
((R+2)(r+5))/3=(3r-30)/(r^2-5r-50)
2. Factor out the common term 3
((R+2)(r+5))/3=(3(r-10))/(r^2-5r-50)
3. Factor r^2-5r-50
((R+2)(r+5))/3=(3(r-10))/((r-10)(r+5))
4. Simplify
((R+2)(r+5)*3(r-10))/(3(r-10)(r+5))
5. Regroup terms
(3(r+2)(r+5)(r-10))/(3(r-10)(r+5))
6. Cancel out (r-10)
(3(r+2)(r+5))/(3(r+5))
7. Cancel out 3 and (r+5)
R+2
Have a nice day
