U9=23dan U13=31 jumblah 25 ke suku pertama barisan tsbt adalah.?
Matematika
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Pertanyaan
U9=23dan U13=31 jumblah 25 ke suku pertama barisan tsbt adalah.?
1 Jawaban
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1. Jawaban Nicoardians
MAPEL: MATEMATIKA
BAB: ARITMETIKA
Jawab:
b= u13-u9/13-9
b= 31-23/4
b= 8/4
b= 2
u1= u9-8b
u1= 23-8(2)
u1= 23-16
u1= 7
s25= n/2(a×2+(n-1)b)
s25= 25/2(7×2+(25-1)2)
s25= 12,5(14+48)
s25= 12,5×62
s25= 775
========>Nicoardians<========