1. x(a+b) / 3(a+b)(a-b) =

 x(a+b) / 3(a+b)(a-b) =

 

Your result is:

1/3 x (a-b) (a+b)^2

wait, but shouldn't it be simplified: 

x/3(a-b)

NO, IT CANNOT BE SIMPLIFIED ANY FURTHER!.

if you want, I will give you a step by step, but it will make you dizzy following it.

IF YOU BRACKET BOTH THE NUMERATOR AND THE DENOMINATOR, THEN THE RESULT IS DIFFERENT:

 

x/(3 (a-b))