You are adding:
5a + 2 a+3
------------ + ---------
6a 3a
The LCD here is 6a, so we must mult. numerator and denom. of the 2nd fraction by 2:
5a + 2 2(a+3) 7a + 8
------------ + --------- = -------------- Please note: either write this result as
6a 2(3a) 6a shown, or include parentheses in your
answer: (7a+8) / (6a)