besar suku ke 30 dari barisan bilangan 0,3,8,15,24

Dik : a = 0
b = 3
c = 2
Dit : U30 = ... ?
2A = c
2A = 2
A = 1

3A+B = b
3(1)+B = 3
B = 0

A+B+C = a
1+0+C = 0
C = -1

Un = An² + Bn + C = (1)n² + (0)n + (-1) = n² - 1
Jadi, U30 = 30² - 1 = 900 - 1 = 899

Semoga Membantu

Kelas 8 Matematika
Bab Barisan dan Deret Bilangan

0, 3, 8, 15, 24, ... → a = 0
...3..5..7....9...... → b = 3
.....2..2..2..... → c = 2
n = 30

Un = a + (n - 1) . b + 1/2 . (n - 1) . (n - 2) . c
U30 = 0 + 29 . 3 + 1/2 . 29 . 28 . 2
U30 = 87 + 812
U30 = 899