Answers

2016-07-07T01:53:40+08:00
*Sn = n/2 (A1 + An) 530 = 10/2 (A + 80) ANSWER: (A = 26) *An = A1 + (n-1)d 80 = 26 + (10-1) d 80 = 26 + 9d 80-26 = 9d 54/9 = 9d/9 ANSWER: (6=d)
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