Question

find a8 when a1=6, r=2

Answer 1

The way you have this problem worded, the r value is irrelevant because there is no r variable in the initial equation. If a to the first power and or a times one equals six then a times eight would be forty-eight but if that is meant to be a^8 then it would equal 1,679,616. I hope this helps but if I'm reading this wrong then just comment on this answer & I will help you.

Answer 2

If this is a Pa

We have the formula:

an = a1 + (n-1).r

Then,

a8 = 6 + (8-1).2

a8 = 6 + 14

a8 = 20

Now, If this is a Pg

Then,

an = a1.r^(n-1)

a8 = 6.2^(8-1)

a8 = 6.2^7

a8 = 6.128

a8 = 768

I believe this would be your question