find the gerneral term

Question

find the general term u_(n)for an arithmetic sequence with u_(4)=8 and u_(11)=-20

Answer 1

4th term = 8

11th term = 20

d = (20-8)/(11-4)= 12/7= 1 5/7 = the common difference

nth term = 1st term + (n-1)d

1st term = 20/7 = 2 6/7

nth term = 20/7 +(n-1)(12/7)