Jawabanmu

2014-05-02T23:52:51+07:00
U6=18
U10 = 30
S16?
 b = (30-18)/ (10-6)
   = 12/4 = 3

U6 = 18
a + (6-1) (3) =18
a + (5)(3) = 18
a + 15 = 18
a = 18 - 15
a = 3

S16 = 16/2 (2 (3) + (16-1)(3))
       = 8 (6 + (15)(3))
      = 8 (6 + 45)
      = 8 (51)
     = 408
2014-05-03T00:12:51+07:00
B= 30-18 per 10-6 = 12/4 = 3
U6 = a+(6-1).3 = 18
            a+5.3 = 18
             a+15 = 18
                   a = 3

Sn = n/2 {2a+(n-1)b
S16 = 16/2 {2.3+(16-1).3}
       = 8.(6+15.3)
       = 8.(6+45)
       = 8.51
       = 408