Answer:
Step-by-step explanation:
The explicit formula for given sequence is: 
Step-by-step explanation:
Given sequence is:
-1,4,-16,64.....
We can see that there is no same difference between consecutive terms so we will find common ratio to see if it is a geometric sequence.
Here

The explicit formula for geometric sequence is:

Putting the values of r and a1

Hence
The explicit formula for given sequence is: 
Keywords: Geometric sequence, common ratio
Learn more about geometric sequence at:
#learnwithBrainly
Answer: 4,1 read carefully
Step-by-step explanation: