<h3><u>Answer:</u></h3>
Hence, the sum of a 7-term geometric series is:
-32766.
<h3><u>Step-by-step explanation:</u></h3>We have to find the sum of a 7-term geometric series (i.e. n=7) if the first term(a) is -6, the last term is -24,576, and the common ratio(r) is 4.
We know that the sum of the 7-term geometric series is given as:
On putting the value of a,n and r in the given formula we have:
Hence, the sum of a 7-term geometric series is:
-32766.