6.) If the first term is 12 and the common difference is 3, find the first four terms of the arithmetic sequence.

7.) If the first term is 2.3 and the common difference is 5.7, find the first four terms of the arithmetic sequence.

8.) If the first term is 7 and the common difference is -5/3, find the first four terms of the arithmetic sequence.

9.) The first term is 8 and the common difference is 2. Find a possible arithmetic sequence formula that models this situation.

10.) The first term is 23 and the common difference is -7/2. Find a possible arithmetic sequence formula that models this situation.

11.) The first term of an arithmetic sequence is -16 and the common difference is 5. Find the 9th term.