What is the sum of a 7-term geometric series if the first term is −11, the last term is −171,875, and the common ratio is −5? −143,231 −36,047 144,177 716,144

The answer is -143,231.

The first step to solving this problem is to find all terms in the sequence. Since this is a geometric sequence, the next term can be found by multiplying the current term by the common ratio.

That means that the second term can be found by: -11×-5 = 55
And the third term can be found by 55×-5 = -275
And so on...

Here are all seven terms:
 -11, 55, -275, 1375, -6875, 34375, -171,875

The next step is to add them all up to find the sum which end up as -143,231, which is your final answer.

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