Jawabanmu

2014-03-03T15:53:32+07:00
B = y-x/ k-1
      21 - 16 / 4+1
       5/5 = 1

jumlah
41 = 16 + (n-1) . 1
41-16 = n-1
25 = n- 1
n =16

S26 = 26/2 ( 16 + 21)
          13 (37) = hitung sendiri
Jawaban paling cerdas!
2014-03-03T16:06:58+07:00
B =  y-x \\ k+1
  =41-16 \\ 4+1
  = 25 \\ 5
  = 5

Un = a+ (n-1)b
41 = 16 + 5n -5
41 = 11+ 5n
30 = 5n
6   = n

jumlah seluruh deret

S6 = 1 \\ 2n (2a +(n-1)b)
     = 1 \\ 2 x 6 (2 x 16 + 25)
     = 3 x 57
     =171
1 5 1