No 46-38 dong plis pake cara !!!

38. U1 = 204 b = u2- u1 = 6
U2 = 210 Un = 294

Un = a + ( n-1 ) b
294 = 204 + (n-1) 6
294 = 204 +6n - 6
294 = 6n + 198
294 - 198 = 6n
96 = 6n
n = 96/ 6 = 16

S16 = 16/2 (204+294)
= 16/2 . 498
= 16 . 249
= 3. 984

semoga bermanfaat :)