Tolong di bantu tolong di bantu tolong di bantu​

Penjelasan dengan langkah-langkah:

9, 13, 17, 21, 25

a = 9

b = 13 – 9 = 4

Suku tengah :

Ut = (9 + 25)/2 = 34/2 = 17

Suku ke-51 :

U51 = 9 + (51 – 1)(4) = 9 + 50(4) = 9 + 200 = 209

Jumlah 50 suku pertama :

S50 = (50/2)(2(9) + (50 – 1)(4)) = 25(18 + 196) = 25(214) = 5350.