.
I will solve and answer parts (a), (b) and (c) only.
a) is the arithmetic progression with the first term 1 and the common difference of 4.
= 1 + 4*(n-1) = 4n - 3.
b) is the arithmetic progression with the first term 70 and the common difference of 50.
= 70 + 50*(n-1) = 50n + 20.
c) is the geometric progression with the first term 1 and the common ratio of 3.
= = .
I just opened your eyes --- you do the rest.
----------------
This problem is about the SIMPLEST properties of arithmetic and geometric progressions.
Learn the subjects from these two groups of introductory lessons in this site
- Arithmetic progressions
- The proofs of the formulas for arithmetic progressions
- Problems on arithmetic progressions
- Word problems on arithmetic progressions
and
- Geometric progressions
- The proofs of the formulas for geometric progressions
- Problems on geometric progressions
- Word problems on geometric progressions
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 topics "Arithmetic progressions" and "Geometric 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.