The formula uppercase S = StartFraction n (a Subscript 1 Baseline plus a Subscript n Baseline) Over 2 EndFraction gives the part
ial sum of an arithmetic sequence. What is the formula solved for an? a Subscript n Baseline = StartFraction 2 uppercase S minus a Subscript 1 Baseline n Over n EndFraction
a Subscript n Baseline = StartFraction 2 uppercase S + a Subscript 1 Baseline n Over n EndFraction
a Subscript n Baseline = 2 uppercase S + a Subscript 1 Baseline n + n
a Subscript n Baseline = 2 uppercase S minus a Subscript 1 Baseline n + n