Sum of the first $4$ terms of an arithmetic sequence is $72$. Sum of the first $9$ terms is also $72$. What is the $5^{\mathrm{th}}$ term of the sequence?

The $7^{\mathrm{th}}$ term of an arithmetic sequence is $10$ and the ${10}^{\text{th}}$ term is $7$ . What is the common difference?

What is the ${21}^{\text{st}}$ term of the arithmetic sequence $21, 20, 19, \dots \dots \dots$?

$5^{\text{th}}$ term of an arithmetic sequence is $17$ and the ${17}^{\text{th}}$ term is $5$. What is the ${44}^{\text{th}}$ term?

First term of an arithmetic sequence is $n$ and the ${\mathrm{n}}^{\text{th}}$ term is $1$. What is the $(\mathrm{n}+1{)}^{\text{th}}$ term?