Proving summation without using inductioni don't understand the part after (r-1)(ar ) and so on, where did (r-1) go?

plz see the other answer w/ corrections below

Step-by-step explanation:

4th row should instead be:  r*Sk - Sk = ar^(k+1) - ar^0

(r-1)Sk = ar^(k+1) - a

Sk = (ar^(k+1) - a) / (r-1)

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i hope this answer you! if you have any further questions or concerns, feel free to ask! : )

step-by-step explanation:

mark brainliest!

a - base

b - exponent

so,