Algebra
posted by Jess on .
I have 3 questions I'm stuck on and would love for someone to explain and show me how to solve them so I can also solve the other one.
Find the partial sum S6
1. An=3n+2
2. Find the number of terms n in an arithmetic sequence if a1=20, d=5, and An=75.
3. Find the general term for 8,17,26,35,44......

3. 8, 8*2+1, 8*3+2, 8*n+n1
or An=9n1 
3. x + 9

#2
Term(n) = a+(n1)d
75 = 20 + (n1)(5)
55 = 5(n1)
11 = n1
n = 12
there are 12 terms 
Thanks for the help bobpursley and Reiny I appreciate showing how you got to it so I can also do it.