Find the indicated sum for each sequence. S9 of –9, 36, –144, 576, ... A –585 B –471,861 C 1,887,435 D –471,852

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Explanation:

This is a geometric sequence because each new term is found by multiplying the last term by -4.

The common ratio is r = -4. The first term is a = -9. We want to sum up n = 9 terms.

Use the geometric nth partial sum formula below to plug in the terms mentioned

47 - 90 = 43

43 - 180 = x

x = 137