SOLUTION: The fifth term of an arithmetic sequence is 23 and the 12th term is 72. 1)Determine the first three terms of the sequence and the nth term? 2) what is the value of the tenth term 3

Algebra ->  Sequences-and-series -> SOLUTION: The fifth term of an arithmetic sequence is 23 and the 12th term is 72. 1)Determine the first three terms of the sequence and the nth term? 2) what is the value of the tenth term 3      Log On


   

Question 1109504: The fifth term of an arithmetic sequence is 23 and the 12th term is 72. 1)Determine the first three terms of the sequence and the nth term? 2) what is the value of the tenth term 3) which term has a value of 268
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
system%28T%5B5%5D=23%2CT%5B12%5D=72%29
This goes through seven common difference increments.

23%2B7%2Ad=72
7d=72-23
7d=49
d=7---------common difference.

A, first term
A%2B%285-1%29%2Ad=23
A%2B4%2A7=23
A=23-28
A=-5-------the term, T%5B1%5D


General Term, highlight_green%28-5%2B7%28n-1%29%29;
Go from there.