dik: U1: 30 b:6 n:16 dit: a. Un: U16? b. banyak jumlah?

a.
Un = a + (n-1)b
U16 = 30 + (16-1)6
= 30 + 15.6
= 30 + 90
= 120

b.
Sn = 1/2n (2a + (n-1)b)
S16 = 1/2.16 (2.30 + (16-1)6)
= 8 (60 + 90)
= 8 (150)
= 1.200

Semoga membantu..

a, u16: 120
cara: u16= u1+(6×15) >> 30+90 = 120
b, jumlah keseluruhan (u1 sampai u16) = 1200
cara:
sn. =1/2n (2.u1 +(n-1)b)
s16 =1/2.16 (2.30 + (16-1) 6)
= 8 (60+15×6)
= 8 (60+90)
= 8×150 >> 1200