s2         1
———————— — ——————
13s2-13s   13s-13

Factor the two denominators:

   s2         1
———————— — ———————
13s(s-1)   13(s-1)

The LCD = 13s(s-1)

The first fraction already has the LCD.
To cause the second fraction to have the LCD, we
notice that it is missing a factor of " s ". So
we multiply it by s/s:

   s2         1       s
———————— — ——————— × ———
13s(s-1)   13(s-1)    s

So now we have:

   s2         s
———————— — ————————
13s(s-1)   13s(s-1)


Since the denominators are now equal, we can combine
the numerators over the common denominator:


  s2-s
————————
13s(s-1) 

Now we factor the numerator:

 s(s-1)
————————
13s(s-1) 

Cancel the s's:
 1
 s(s-1)
————————
13s(s-1)
  1 

 (s-1)
———————
13(s-1)

Cancel the (s-1)'s

   1
 (s-1)
———————
13(s-1)
    1

  1
————
 13

Edwin
AnlytcPhil@aol.com