To solve this equation, we first need to find a common denominator for the fractions.

First, let's convert 7/12 to a fraction with a common denominator with 1/9:

7/12 = 63/108

Now, let's add 63/108 and 1/9:

63/108 + 1/9 = (63 + 12) / 108 = 75/108

Now, let's convert 2/3 to a fraction with a common denominator with 1/6:

2/3 = 72/108

Now, let's divide the sum of (75/108 + 72/108) by 3:

(75/108 + 72/108) / 3 = 147/108 / 3 = 49/36

Therefore, the final answer is 49/36.