Banyaknya suku pada barisan -4, 0, 4 ......, 36 adalah... A. 8 B. 11 C.14 D. 17 E. 20

Bab Barisan dan Deret
Matematika SMP Kelas VIII

b = U2 - U1
b = 0 - (-4)
b = 0 + 4
b = 4

Un = 36
a + (n - 1) b = 36
-4 + (n - 1) . 4 = 36
(n - 1) . 4 = 36 + 4
n - 1 = 40/4
n = 10 + 1
n = 11

Un=a+(n-1)b
= -4+(n-1).4=36
= -4+4n -4=36
=4n-8=36
=4n=36+8
=4n=44
n=11(B)