9+10+11+12....+124=....
Matematika
mirnayosefin
Pertanyaan
9+10+11+12....+124=....
1 Jawaban
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1. Jawaban Machzen
A = 9
B = 10-9 = 1
Un = 124 + 1 -9 = 116
S116 :
= n/2 [a x b + (n-1) x b]
= 116/2 [9 x 1 + (116-1) x 1]
= 58 [9 + 115]
= 58 x 124
= 7.192