From the recursive rule, you can tell the initial value is 3 and the common ratio is 12. The explicit rule is always
.. (n-th term) = (initial value)*(common ratio)^(n -1)
Subsituting the values you know, you have
.. an = 3*12^(n-1)
Answer:

Step-by-step explanation:
If you add a number that is negative, you are basically subtracting it.
This means that

Since they both have the same denominator, you can easily subtract the fractions: 