if a1=7 and an=5an what is the value of a6

Question

idk

Answer 1

a1=7

maybe you left out -1. if so then

an=5an-1

a1=7

a2=5a1= 5(7)=35

a3=5a2=5(35)=175

a4=875

a5=4375

a6=21,875

an =5an-1=a1(5^(n-1)

a6=7(5^(6-1))=7(5^5)=7(3125)=218757

it's a geometric series with r= common ratio =5

an=a1(r^(n-1))