Question

The 15th term of an arithmetic series is

143 and the 31st term is 183.
a) Find the first term and the common
difference.
b) Find the 100th term of the series.

Answer 1

-1557

Explanation:

a+14d=143

a+12d=183

--------------------

2d= -40

d= -20

a=183+240=423

a(100th)= 423+99*-20=423-1980= -1557

I hope that help =)