Answer:
g(3a - 6) = a - 4
Explanation:
If you start with g(x) = 1/3 x - 2
Then whatever x = on the left, must take on the value on the right.
g(3a - 6) = 1/3 (3a - 6) - 2 Notice the x is gone and 3a - 6 has taken it's place.
Now you must distribute the 1/3 for both 2a and 6
g(3a - 6) = 1/3 * 3a - 1/3 * 6 - 2
g(3a - 6) = a - 2 - 2
g(3a - 6) = a - 4