Question

What is the 9th term of this arithmetic sequence?

2a - b, a, b, .....

Answer 1

let's find the common difference between each term I guess...

Answer 2

the common difference is

d=a-(2a-b)=b-a

so we have up to the third term b
4th term b+(b-a)=2b-a
5th term 2b-a+(b-a)=3b-2a
with the common difference you should be able to figure out what the nth term is.

if not, just do it manually ;)

Answer 3

Thanks!!

Answer 4

welcome :)