2-4 plaese jawab besok mau ngumpul

2) Un=a+(n-1)b
U10=3+(10-1)4
=3+36
=39
3) un=6+(9-1)5
=6+40
=46
4) un =ar^n-1
un18= 4.2^18-1
=4.2^17
=4.131072
=524288

no4 gak sebarapa yakin..
semoga dapat membantu