How to find first term and commond difference if the only given are the last term (80) and sum of first 10 terms (530)?
1 Answer
Explanation:
This is an arithmetic series.
The
Where
The sum of an arithmetic series is given as:
We are given:
Sum of the first 10 terms is
Using in
Last term is 80:
Using this in
Solving
in
Substituting in
First term is:
The common difference is:
Check:
last term:
Sum of first 10 terms: