5+13+21+....+181=...
Matematika
Kathleen11
Pertanyaan
5+13+21+....+181=...
1 Jawaban
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1. Jawaban KutuBuku01
181 = 5 + ( n-1 ) 8
181 = 5 + 8n - 8
181 = 8n - 3
8n = 184
n = 23
S23 = 23/2 (2x5+(23-1)8)
S23 = 23/2 x 186
S23 = 2.139