<h3>Answer:</h3>
The common ratio is -8/4 = -2. The general formula for the n-th term is ...
... an = a1·r^(n-1) . . . . . . note the use of the caret (^) and parentheses
For r = -2 and a1 = 4, this becomes ...
... an = 4·(-2)^(n-1) . . . . approximately matches the 2nd selection