Question

Which rule can you use to find the nth term of an arithmetic sequence in which the common difference is 5 and a12 = 63?

Answer 1

Tn = a + (n-1)d

when n  = 12, tn  = 63

63 = a + (12-1)*5

a = 63 - 55 =8

tn or an 
= 8 + (n-1) 5

=  3 + 5n

Hope this helps