Question

what is the sum of a -7 term geometric series if the first term is -6, the last term is -24576 and the common ratio is -4 ?

Answer 1

Well, in a geometric series you are basically multiplying things over and over again. So if your first term is -6 and your common ratio is -4 that basically means that your geometric sequence is{-6,-6*-4,-6*-4*-4,-6*-4*-4*-4,...}. Now, since we know that it's only 7 terms long we can just follow that process until we have 7 terms in the sequence (the last term you will get is -24576). Once you have the sequence you just need to add up all the terms and you'll get the solution.