9514 1404 393
Answer:
an = 3(-4)^(n-1)
Explanation:
The explicit formula for a geometric sequence with first term a1 and common ratio r is ...
an = a1(r^(n-1))
The given sequence has a first term of 3 and a common ratio of -12/3 = -4. The explicit formula is ...
an = 3(-4)^(n-1)