20,15,10,5,.....S41=....
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Jawaban:
3280
Penjelasan dengan langkah-langkah:
a = 20
b = 15-20 = -5
[tex]sn = \frac{n}{2} \times (2(a) + (n - 1)b) \\ \\ s41 = \frac{41}{2} \times (2(20) + (41 - 1)( - 5)) \\ \\ s41 = \frac{41}{2} \times (40 + ( - 200)) \\ \\ s41 = \frac{41}{2} \times 160 \\ \\ s41 = (41) \times 80 = 3280[/tex]
[answer.2.content]
