Answers

2016-06-29T21:36:09+08:00
2016-06-30T19:47:06+08:00
Sn= n/2 [2a1+(n-1)d]
S8= 8/2 [2(2)+(8-1)3]
S8= 4[4+21]
S8= 4[25]
S8= 100
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