Respuesta :

9+18s-7s the common factor is 's' so : s(18-7) + 9 and that is : 11s+9 The answer is B.
As 9+18s-7s
   =9+11s
As 9+18s-7s=9+11s
9+18s-7 is Option "B"....

Hope this may help u!!!!