Finding the explicit formula of an arithmetic sequence

Question

Hi! I need to find the explicit formula of an arithmetic sequence with a term a₃₈ = -53.2 and the common difference -1.1. How should I go about this? Thank you! :)

Answer 1

a38 = -53.2

common difference = -1.1 = d

an= a1 + d(n-1)

a38 = -53.2 = a1 -1.1(37) = a1 - 40.7

a1 = -53.2 + 40.7 = -12.5

an= -12.5 -1.1(n-1)