.
There are 30-16 = 14 gaps between the terms and .
Each gap is = 7 units long.
So, the 16-th term of the arithmetic progression is = 105, and the common difference is d = 7.
Now you can find the first term from the equation
= + 7*15,
105 = + 105
= 0.
Hence, the formula for the general term is
= + d*(n-1) = 0 + 7*(n-1) = 7*(n-1).
That's all. Solved, explained and completed.
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For introductory lessons on arithmetic progressions see
- Arithmetic progressions
- The proofs of the formulas for arithmetic progressions
- Problems on arithmetic progressions
- Word problems on arithmetic progressions
in this site.
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Arithmetic progressions".
Save the link to this textbook together with its description
Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson
into your archive and use when it is needed.