Tolong jawab ya. Bsk mau dikumpulin. Pkak cara

a). 5.8.11.14,...
Un= 3n+2
U12= 3(12)+2
U12= 36+2
U12= 38

b). 1.3.5.7,...
Un= 2n-1
U12= 2(12)-1
U12= 24-1
U12=23

c). 10.11.12.13,...
Un= 9+n
U12= 9+12
U12= 21

cuma tau 3 Nomor kak, semoga dapat membantu!