algebra
posted by bb .
What is the common denominator?
3 2
 + 
1 a1

4 3
  
1 a+1

If your denominator on the top is (a1) and your denominator on the bottom is (a+1) then your common denominator is (a1)(a+1) which by the way is (a^21)

Thank you very much. It helped me not only on that problem but others as well. :)

"........but others as well."
Good! That is the whole idea :) You are very welcome.