Math ( Can You check my Work?)
posted by Tony .
1.an = 3n  1
2. an = 2(2n  3)
3.an = 4^n
4.an = (2/3)^n
5. an = (1)^n(n + 5)
6. an = (1)^n + 1(n + 6)
7. an= n+3/2n1
8. a1 = 5 and an = an1  3 for n ≥ 2
9. a1 = 6 and an = 2an1 for n ≥ 2
10.a1 = 4 and an = 3an1 + 2 for n ≥ 2
11. Find a8 when a1 = 10, d = 3.
3 points
Question 16
Use the formula for the general term (the nth term) of an arithmetic sequence to find the indicated term of the sequence with the given first term, a1, and common difference, d.
Find a21 when a1 = 28, d = 5.
Answer
77
128
100
72
3 points
Question 17
Write a formula for the general term (the nth term) of the arithmetic sequence. Then use the formula for an to find a20, the 20th term of the sequence.
1, 4, 7, 10, 13, . . .
Answer
an = 3n + 2; a20 = 62
an = n + 3; a20 = 23
an = 3n  2; a20 = 58
an = 2n  3; a20 = 37
3 points
Question 18
Write a formula for the general term (the nth term) of the arithmetic sequence. Then use the formula for an to find a20, the 20th term of the sequence.
25, 16 , 7, 2, . . .
Answer
an = 9n + 25; a20 = 155
an = 9n + 34; a20 = 146
an = 9n  25; a20 = 155
an = 9n  34; a20 = 146
3 points
Question 19
Solve the problem.
The population of a town is increasing by 200 inhabitants each year. If its population at the beginning of 1990 was 27,842, what was its population at the beginning of 1998?
Answer
222,680 inhabitants
29,442 inhabitants
29,242 inhabitants
445,360 inhabitants
3 points
Question 20
Find the indicated sum.
Find the sum of the first 50 terms of the arithmetic sequence: 3, 4, 11, 18, . . .
Answer
8600
8425
347
8420
3 points
Question 21
Find the indicated sum.
Find the sum of the first 48 terms of the arithmetic sequence: 2, 4, 6, 8, . . .
Answer
98
2359
2400
2352
Just reply if you can check my work and i will post my answers again

I see problems and answer choices, but I don't see any of your work to check.
How do the first 11 expressions relate to the rest of the post?