nomer 15 yaaaaaaaaa............

U1 = 44
b = 4

Un = 148
a + (n-1)4 = 148
44 + (n-1)4 = 148
(n-1) = 104/ 4
n-1 = 26
n = 27

Maka
S27
= 27/2 (2(44) + 26(4))
= 27(44 + 52)
= 27(96)
= 2.592

Sn=n/2 (Un + a)
S27=27/2 (148 + 44)
S27=27/2 ( 192)
S27=27 x 96
S27= 2592