tentukan rumus suku ke n dari bilangan 4,8,14,22

a......4.....8.....14.....22.....
b.........4......6......8....
c..............2......2.....

a = 4
b = 4
c = 2

• 2A = c
2A = 2 ---> A = 1

• 3A + B = b
3A + B = 4 ---> B = 1

• A + B + C = a
1 + 1 + C = 4 ---> C = 2

⏺ Un = An² + Bn + C
Un = n² + n + 2